Mercury (Budh) in Vedic astrology: what BPHS, Saravali and Bhrigu Sutras say, and how to read it in your chart

Mercury is the graha the classical texts hand speech to. BPHS calls it the speech-giver and the prince, Saravali the voice of the Kalapurusha, and Bhrigu Sutras calls it convertible. That last word explains most of what follows. Mercury is counted a benefic, but one that takes on the nature of whatever it sits with, and what it sits with most is the Sun: it is never more than about 28 degrees away.

This page sets out what Brihat Parashara Hora Shastra (BPHS), Saravali and Bhrigu Sutras say about Mercury, with chapter and sloka, where they disagree, and what this app's engine does with each rule. It is a map of rules, not a forecast about anyone. To see your own Mercury, with its sign, degree, house and whether it is retrograde or combust, cast a chart with the Birth Chart calculator.

Budh at a glance

BPHS Ch. 3 and Saravali Ch. 4 list each graha's attributes, and the modern introduction to Bhrigu Sutras adds its own. Where they differ, both readings are shown.

What Mercury signifies

BPHS Ch. 3 Sl. 12-13 gives each graha one governance: the Sun the soul, the Moon the mind, Mars strength, and Mercury speech. Saravali Ch. 4 Sl. 1-2 says the same of the Kalapurusha and adds the working rule that a signification is strong when its graha is strong at birth and meagre when it is weak. BPHS Ch. 3 Sl. 26 describes Mercury as attractive in build, able to use words with many meanings, and fond of jokes; Saravali Ch. 4 Sl. 24 adds sweet, clear speech and skill.

The practical lists are specific. BPHS Ch. 70 Sl. 1-6 names what is judged from Mercury: business dealings, livelihood and friends. Ch. 32 Sl. 18-21 makes it the fixed significator of maternal relatives, Sl. 22-24 reads the maternal uncle from the 6th house counted from Mercury, and in the list of house significators at Sl. 31-34 Mercury holds the 10th. Saravali Ch. 7 Sl. 7-13 gives it the Veda, writing, sculpture, medicines, expertise, ministership, speech, jokes, birds and fame. (This copy also prints a second list under Mercury's name, beginning with minerals and earth, straight after Mars's; it is not used here.) Bhrigu Sutras narrows the intellect Mercury rules to the part that can be trained by study, observation and imitation, and names Mercury the chief governor of education and of the uncle.

Each of these texts also assigns body associations. BPHS gives Mercury the skin (Ch. 3 Sl. 31); Bhrigu Sutras lists the nervous system, bowels, arms, mouth and tongue. These are reported as classification, not medical advice, and this app makes no health prediction from them.

Two parts of this app read Mercury directly. The Career and Money calculator treats it as the significator of trade, accounts and negotiation: a Mercury rated Strong counts toward running your own business, a Weak one toward a role where someone else owns the commercial side. And the communication reading in the Compatibility feature starts from each person's Mercury: its sign and element, dignity, house, and whether it is retrograde or combust.

A benefic that takes on its company

BPHS Ch. 3 Sl. 11 lists the malefics, calls the rest benefics, and adds one exception: Mercury is a malefic if it joins a malefic. Ch. 34 Sl. 8-10 puts it more exactly. Jupiter and Venus are benefics, the Moon is middling, and Mercury is neutral: a benefic with a benefic and a malefic with a malefic. Saravali Ch. 4 Sl. 9 agrees, and the translator's note to BPHS Ch. 3 adds that Mercury with a waning Moon leaves both benefic. Bhrigu Sutras' commentary on the 1st house widens the conditions: Mercury is a benefic unless it is joined or aspected by a malefic, or combust.

The same BPHS slokas rank the benefics. The full Moon, Mercury, Jupiter and Venus are stronger in that ascending order, so Mercury is the second-mildest benefic. When a benefic's ownership of angles spoils it, the same order applies, and Mercury is the second-least affected.

This engine does not apply the conversion. It counts Mercury among its benefics unconditionally, with Jupiter, Venus and the Moon: a Mercury aspect raises another planet's Shad Bala, Mercury's transits follow the benefic rule, and Mercury can form the benefic yogas. Two of those yogas, Chandradhi (Adhi) and Amala, carry their own test, which is that the benefic must not share a house with, or be aspected by, the Sun, Mars, Saturn, Rahu or Ketu. Mercury shares the Sun's sign on about half of all days, so that test removes it often. The engine's Kendradhipati Dosha leaves Mercury out altogether; its code comment cites its source as calling Mercury only half-inclined to that fault.

Dignity: Virgo, Gemini and Pisces

Exalted in a sign it owns

Mercury is the only graha exalted in a sign it also rules. BPHS Ch. 3 Sl. 49-50 exalts it in Virgo, deepest at 15 degrees, with its fall in the seventh sign from there, Pisces, at the same degree. Sl. 51-54 then cut Virgo into three: the first 15 degrees are the exaltation zone, the next 5 the Moolatrikona, the last 10 its own sign. Saravali Ch. 5 Sl. 21-24 and Bhrigu Sutras give the same three bands, and Bhrigu Sutras adds that the whole of Gemini is its own sign. Each sign has its page: Virgo, Gemini and Pisces.

This engine keeps the same signs and the same three-way split of Virgo. Its dignity function labels Mercury Exalted below 15 degrees, Moolatrikona from 15 to 20 and Own sign from 20, so the last ten degrees score 7.5 for position on the engine's ladder rather than 10; BPHS gives own sign half the good effect (Ch. 3 Sl. 59-60). The one-line reading for each house lord and the current dasha lord's action guidance pass the same degree, so they follow the same three bands.

Friends, enemies, and the half that depends on your chart

BPHS Ch. 3 Sl. 55 derives natural friendship from the Moolatrikona sign. The lords of the 2nd, 4th, 5th, 8th, 9th and 12th signs from it, with the lord of the exaltation sign, are friends; the rest are enemies; a graha on both lists is neutral. Counted from Virgo, the friendly signs are Libra and Taurus (Venus), Sagittarius (Jupiter), Capricorn (Saturn), Aries (Mars) and Leo (the Sun). The signs left over are Scorpio (Mars), Aquarius (Saturn), Pisces (Jupiter) and Cancer (the Moon). Mars, Jupiter and Saturn land on both lists and are neutral; Venus and the Sun are friends; the Moon alone is an enemy. Saravali Ch. 4 Sl. 28-29 and Bhrigu Sutras state exactly that list, and the engine stores it. The feeling is not mutual: in the same Saravali sloka the Moon, Venus and Saturn count Mercury a friend, and Mars and Jupiter count it an enemy.

That is half the grading. BPHS Ch. 3 Sl. 56 adds a temporary relationship read from the chart: a graha in the 2nd, 3rd, 4th, 10th, 11th or 12th sign from another is its friend there, and anywhere else, the same sign included, its enemy. Sl. 57-58 combine the two, as Saravali Ch. 4 Sl. 30-31 does: friend on both counts is a great friend, friend and enemy cancel to neutral, neutral plus friend is a friend, neutral plus enemy an enemy. The engine's dignityOf() implements exactly this, but only when it is handed the chart; without one it uses the natural relation alone. The Shad Bala, planet-in-house and Mahadasha readings pass your chart, so the label you see is the fourth or fifth column; the third is the natural relation alone.

For Mercury two of those rows are nearly decided in advance. Mercury is never more than one sign from the Sun, so with Mercury in Leo the Sun is either beside it in Leo, a temporary enemy, or in Cancer or Virgo, a temporary friend. By Sl. 56-58 a Leo Mercury is in a friend's sign in full only when the Sun is not with it. Venus stays within three signs of Mercury (73.76 degrees at most in a century of this engine's positions), so in Taurus or Libra Mercury drops a grade only when Venus shares its sign, which was about a quarter of days.

Saravali Ch. 45 gives one line for Mercury in each state. Exalted: intelligent, foremost in the family, a skilful speaker. Moolatrikona: jocular and successful. Own sign: a sweet speaker and learned. A friend's sign: skilful, jocular and rich. Debilitated: mean, and at odds with cousins and relatives. An enemy's sign: short of intelligence and of money. Rays are a separate measure. Saravali Ch. 36 Sl. 2 gives Mercury 5 rays at exaltation in one school, Sl. 3-4 gives every graha 7 in the majority view this engine follows, and Sl. 6 counts them from the distance to the deep fall point alone. So Mercury in Gemini, its own sign, collects 3.31 rays at 10 degrees, fewer than in Leo or Libra, because Gemini is only 85 degrees from 15 degrees of Pisces. The Deep Dive on your Kundali shows rays beside dignity, not instead of it.

When and where Mercury is strong

Mercury's strength rules are the most even-handed of any graha's. Where others are strong by day or by night, in one half-year or the other, Mercury is credited in both.

• Direction. BPHS Ch. 3 Sl. 35-38 and Saravali Ch. 4 Sl. 35 make Mercury, with Jupiter, strong in the East, the Ascendant. BPHS Ch. 27 Sl. 7 computes it from the arc between Mercury and the 7th house, so it peaks in the 1st and vanishes in the 7th; Advanced Predictive Astrology (Vol. II, p. 31) repeats the rule. The engine gives full directional strength in the 1st house and none in the 7th, falling evenly between.
• Day and night. Mercury is strong during both (BPHS Ch. 3 Sl. 35-38; Saravali Ch. 4 Sl. 36), and BPHS Ch. 27 Sl. 8-9 gives it full day-night strength whatever the hour. The engine gives Mercury full time strength in every chart it scores. Mercury also holds the first third of the daytime (BPHS Ch. 27 Sl. 12; Saravali Ch. 4 Sl. 39), which the engine does not compute.
• Half-year. Saravali Ch. 4 Sl. 37 makes Mercury strong in both the northern and the southern course, and BPHS Ch. 27 Sl. 15-17 always adds, never subtracts, in Mercury's Ayana strength.
• Motion and sign. Saravali Ch. 4 Sl. 36 counts a retrograde planet strong. The engine credits Mercury's motional strength when it is retrograde, and also whenever it is in Gemini or Virgo, following its own source.
• Nature. BPHS Ch. 3 Sl. 38, Ch. 27 Sl. 14 and Saravali Ch. 4 Sl. 40 rank natural strength Saturn, Mars, Mercury, Jupiter, Venus, Moon, Sun, weakest first. Mercury is third from the bottom, at three sevenths of a Rupa; the engine gives it 0.375 of 1.
• Decanate and parity. The texts disagree about the decanate: BPHS Ch. 27 Sl. 6 gives a neuter graha its quarter Rupa in the third decanate of a sign, Saravali Ch. 4 Sl. 38 in the second. Both make Mercury stronger in odd signs (BPHS Ch. 27 Sl. 4.5; Saravali Ch. 4 Sl. 35). The engine computes neither.
• Houses it sits in. BPHS Ch. 27 Sl. 30-31 adds one Rupa to the strength of a house occupied by Mercury or Jupiter, and Sl. 19 adds the aspects of those two in full to a planet's aspect strength. The engine does not compute Bhava Bala.

BPHS Ch. 27 Sl. 32-33 then sets the bar. Mercury needs 420 Virupas of Shad Bala to count as strong, the highest requirement of the seven; the Sun and Jupiter need 390, Mars and Saturn 300. That figure belongs to BPHS's full Virupa computation. The Shad Bala calculator runs a simplified 20-point version from the engine's own source, so its numbers cannot be compared with 420; on that scale Mercury can score between 1.375 and 19.375. For BPHS's separate twenty-point divisional strength (Ch. 7 Sl. 9-12), use the Vimshopaka Bala calculator.

Combustion and retrogression: Mercury's two ordinary states

Two conditions the texts treat as special are routine for Mercury. Bhrigu Sutras notes that it is never more than 28 degrees from the Sun, treats it as combust within 8.5 degrees, and says its influence is best when it is moving away from the Sun. This engine uses a 14-degree orb for Mercury. Run day by day across 1950-2049 on the engine's own positions:

What the texts say of the two states pulls in opposite directions. Combustion weakens: Saravali Ch. 5 Sl. 2-4 names the combust state Vikala, mutilated, Sl. 27 says a planet combust by the Sun loses its power for good, Ch. 36 Sl. 7-9 strips its rays, and Ch. 41 Sl. 7 counts a combust lord's Dasa inauspicious. Retrogression strengthens a benefic (Saravali Ch. 5 Sl. 39), though Ch. 5 Sl. 14 records the view that a planet retrograde in its exaltation sign gives nothing. BPHS Ch. 47 Sl. 3-4 adds a timing effect: a retrograde Dasha lord delivers its results in reverse order. For Mercury the two usually arrive together. On nearly three retrograde days in four it was also combust.

In the engine, a combust planet loses its whole position score in Shad Bala, whatever its sign. For Mercury the arithmetic has a consequence. The other five components can add at most 9.375, and the Strong band starts at 13, so a combust Mercury can never be rated Strong, and Mercury is combust on more than two days in five. A retrograde Mercury gains the one point of motional strength. The chart flags both states for every planet.

One real chart shows how far the readings can part. For 10 September 2026, 06:50 IST, New Delhi, the engine gives Virgo rising and Mercury at 4.72 degrees of Virgo in the 1st house, 11.6 degrees from the Sun in Leo, aspected by Mars from the 10th and Saturn from the 7th. Dignity: Exalted. Directional strength: full. Yogas: Bhadra. Planet row and Mahadasha reading: favourable. Rays: 6.60 of 7. Shad Bala: 6.38 of 20, Weak, because combustion removed the position score and two malefic aspects removed the aspect score. None of these is an error. Each measures one thing, and the chart has to be read with all of them on the table.

Aspects: what Mercury sees, and what can see it

BPHS Ch. 26 Sl. 2-5 gives every graha a full aspect on the 7th place from itself and graded partial aspects elsewhere; only Saturn, Jupiter and Mars have special full aspects. Mercury's one full aspect is the 7th, and this engine, which counts full aspects only, has Mercury aspect exactly one house in your chart. That aspect has a named use. BPHS Ch. 42 Sl. 16-18 says Mars and Saturn together in the 2nd house damage wealth, and that Mercury's aspect on them reverses the result. The engine implements both halves: its Dhan Bhava caution for Mars and Saturn in the 2nd is lifted when Mercury sits in the 8th.

Saravali Ch. 26 Sl. 25-66 reads each graha's aspect on Mercury, grouped by the lord of Mercury's sign. Jupiter's aspect is favourable in every group: riches and command in the signs of Mars, learning and leadership in Venus's, a king's minister in Mercury's own, a great scholar in Cancer, a gifted speaker in Leo, a minister or treasurer and a writer in Jupiter's own, money and local honour in Saturn's. Saturn's aspect is unfavourable in every group but one. In Mercury's own signs it gives a modest, forward-looking person who succeeds in what he starts.

The same chapter reads the Sun's aspect on Mercury too, and that one cannot occur. An aspect needs distance. BPHS's smallest partial aspect falls on the 3rd sign, and Mercury is never more than one sign from the Sun. Venus cannot cast a full aspect on Mercury either, since it stays within three signs of it. Their influence on Mercury in a real chart is by conjunction or from neighbouring signs.

What Mercury rules from your Lagna

Mercury owns Gemini and Virgo, so the Lagna fixes two houses it rules, and BPHS Ch. 34 names its role for most rising signs. The Yoga Karaka panel on the Kundali reproduces those lists. Confirm your rising sign with the Lagna calculator.

The general rules at Ch. 34 Sl. 2-7 explain most of the column. Lords of the 3rd, 6th and 11th give evil effects, which covers Aries, Cancer, Leo and Scorpio. A trine lord is auspicious, which lifts Mercury for Libra and Capricorn through the 9th even though its other sign is a difficult house. A benefic owning angles loses its beneficence, which is why Pisces, where Mercury owns two angles and nothing else, is its hardest Lagna; for Sagittarius, with the same pattern, the text still credits a Yoga with the Sun, lord of the 9th. "Killer" is the technical term BPHS Ch. 44 attaches to the lords of the 2nd and 7th houses. This app shows the label and computes no death timing.

Lordship also feeds three of the engine's yogas. Its Raja Yoga needs the 5th and 9th lords in one house; Mercury is the 5th lord for Taurus and Aquarius Lagnas and the 9th for Libra and Capricorn. Its Dharma-Karmadhipati Yoga needs the 9th and 10th lords together in an angle or trine; Mercury is the 10th lord for Virgo and Sagittarius. And its Vipareeta Raja Yogas form when the lord of the 6th, 8th or 12th sits in one of those houses; Mercury is such a lord for Aries, Cancer, Libra, Scorpio, Capricorn and Aquarius. The Yogas calculator lists them when your chart has them, and what a yoga in your chart means explains how to weigh the entries.

Mercury in the twelve signs

Saravali Ch. 26 gives a reading for Mercury in each sign, without reference to house. The table keeps its lines on learning, speech and occupation and leaves out its harsher character verdicts and its sexual lines. This app prints a one-line temperament for the Sun's sign and the Moon's only; it has none for Mercury, so the middle column is the text's and the last is the engine's dignity label without the chart.

The readings track dignity only loosely. Saravali is generous to Mercury in Sagittarius, whose lord counts Mercury an enemy, and hard on it in Leo, a friend's sign. Dignity measures how comfortable Mercury is in a sign; the sign readings describe what the sign's nature does to Mercury's.

Mercury with another graha

Saravali Ch. 15 gives the effect of two planets in one house. Its Mercury pairs, with the harsher lines left out:

• With the Sun (Sl. 4): in service, sweet in speech, with fame, money and learning, dear to the king and to good people; wealth is unsteady. Advanced Predictive Astrology (Vol. II, p. 58) calls this pair Budhaditya Yoga in a case study. This app does not list it as a yoga; in the engine's positions Mercury shared the Sun's sign on 51 per cent of days.
• With the Moon (Sl. 9): skilled in poems and fables, wealthy, pleasant, smiling.
• With Mars (Sl. 13): little wealth; works with gold and iron, an architect, skilled in making medicines. Advanced Predictive Astrology (Vol. II, p. 156) reads the pair as an eloquent but disputatious speaker, good for lawyers.
• With Jupiter (Sl. 17): a noted dancer, scholar, singer and instrumentalist; wise and happy.
• With Venus (Sl. 18): very rich, a politician and artisan, a student of the Vedas, good in speech, fond of song and fun.
• With Saturn (Sl. 19): an able poet, expert, restless and in debt, with auspicious speech; the sloka also calls him proud and deceiving.

Sl. 23 adds that each result rises or falls with the vargas the two planets occupy. By BPHS's rule, any malefic in this list also changes Mercury's own nature.

Yogas Mercury takes part in

Bhadra, the Mahapurusha yoga

BPHS Ch. 75 Sl. 1-2 and Saravali Ch. 37 Sl. 2 give Mercury one of the five Panchamahapurusha yogas: Bhadra, formed when Mercury is in its own or exaltation sign and in an angle from the Lagna. BPHS Sl. 8-12 describes the Bhadra native as learned in every respect, versed in the shastras, independent by nature, a protector of family whose friends share his wealth; Saravali Sl. 14-18 agrees on learning and independence. Both add body measurements, palm marks, a region ruled and an age at death, none of which is repeated here. Saravali Ch. 41 Sl. 74 says such a yoga's effects come in the Dasa of its planet.

The rule has a consequence the texts do not spell out. Gemini and Virgo are angles only for the four dual Lagnas, Gemini, Virgo, Sagittarius and Pisces, so no other rising sign can have Bhadra Yoga. Sampled every 97 minutes across 1950-2049, the engine's rule was met 5.48 per cent of the time, about one birth in eighteen. The engine prints its own one-line trait for it: sharp-minded and articulate, well-read, independent-natured and protective of family.

Beside the Sun and the Moon

A planet in the 2nd sign from the Sun forms Vesi and one in the 12th forms Vasi (Saravali Ch. 14 Sl. 1; BPHS Ch. 38 Sl. 1 spells it Vosi). Mercury is a frequent cause: it was in the 2nd from the Sun on 24.5 per cent of days and in the 12th on another 24.5. Saravali reads Mercury's versions modestly. Causing Vesi (Sl. 3-5): soft-spoken, modest and bashful, in service, short of money. Causing Vasi (Sl. 7-9): sweet in speech, good-looking, obedient to others' orders. Sl. 10 asks for the strength of the Sun and of the causing planet to be weighed first.

Around the Moon the same geometry gives Sunapha (2nd) and Anapha (12th), by Saravali Ch. 13 Sl. 1. Mercury causing Sunapha (Sl. 10-11) makes one expert in the Vedas, shastras and music, a poet, high-minded; causing Anapha (Sl. 15-19), expert in singing, dancing and writing, an able orator honoured by the ruler. The engine detects all four yogas by whole sign and names the planets that form them, but prints one general line per yoga, not the planet-by-planet reading.

Wealth and learning combinations

BPHS Ch. 41 names two wealth combinations built on Mercury, and the engine checks both. Sl. 3: Mercury in its own sign in the 5th house with the Moon, Mars and Jupiter in the 11th. Sl. 12: Mercury in its own sign in the Lagna, joined or aspected by Saturn and Jupiter. Each needs an exact coincidence and is rare by design. BPHS Ch. 36 adds Sharada Yoga (Sl. 19-20: the 10th lord in the 5th, Mercury in an angle and a strong Sun in Leo; or Jupiter or Mercury in a trine from the Moon with Mars in the 11th) and Kalanidhi Yoga (Sl. 31-32: Jupiter in the 2nd or 5th aspected by Mercury and Venus). Those two are not coded, so their absence from the Yogas calculator says nothing about your chart.

Mercury in the twelve houses

Each house has its own page, built from Bhrigu Sutras' Mercury chapter, Saravali Ch. 30 and the BPHS chapters on each house. In this app the planet row for Mercury reads a favourable sentence when Mercury's dignity is exalted, own or friendly and it is outside the 6th, 8th and 12th; otherwise a testing sentence. The favourable sentences, written from Bhrigu Sutras, beside Saravali's:

Three houses need a note. In the 5th the sources split: Bhrigu Sutras (Sutras 38-40) expects difficulty in having children, while Saravali gives many. In the 8th they agree, and against the general rule. Saravali Ch. 30 Sl. 86-87 says benefics do badly in the 6th, 8th and 12th, yet its own Sl. 45 and Bhrigu Sutras (Sutras 57-63: long life, land and reputation) both read Mercury there as favourable. This app follows the general rule, so a Mercury in the 8th always gets the testing sentence, even exalted. And the 10th and 11th are where every authority the Bhrigu Sutras commentary quotes agrees Mercury does best.

The house pages: Mercury in the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 11th and 12th. Because Mercury is never more than one sign from the Sun, its house is always the Sun's house or the one on either side, and the Sun's house follows the clock: the 1st around sunrise, the 10th around midday, the 7th around sunset, the 4th around midnight. A midday birth with Mercury in the 4th means the time or the place needs checking first; what a missing birth time does explains what can still be read without one.

Mercury's Ashtakavarga: 54 points out of 96

In Mercury's own Ashtakavarga each of eight contributors, the seven grahas and the Lagna, marks the places counted from itself that are good for Mercury. This engine's table gives 54 such points. The most generous place is the 11th, marked by all eight contributors, then the 8th with six; the leanest are the 3rd and 7th with two each. BPHS Ch. 66 Sl. 28-30 counts the bad marks place by place, 42 in all, and the engine's table is its exact complement in all twelve places. The good-mark list at Sl. 51-52 matches in eleven. In the 5th place this translation prints Saturn, which Sl. 28-30 has already listed among the bad marks there; the engine has the Sun, the reading that keeps the two slokas consistent. One caution on words: BPHS marks bad places with dots (bindus) and good ones with lines (rekhas), while this app calls the good points bindus. The Ashtakavarga calculator returns Mercury's row house by house.

BPHS Ch. 70 Sl. 28-29 says what the row is for: family, the maternal uncle and friends are considered from the 4th house counted from Mercury. This app's transit reading uses a different measure, the combined Sarvashtakavarga against your chart's own average.

Timing: Mercury's dashas

In Vimshottari Mercury rules 17 of the 120 years (BPHS Ch. 46 Sl. 15), after Saturn's nineteen and before Ketu's seven. Ch. 46 Sl. 12-14 counts the lords from Krittika, which gives Mercury Ashlesha, Jyeshtha and Revati; a Moon in any of the three starts life in Mercury's Mahadasha with at most seventeen years of it left. The arithmetic is in what a Mahadasha is, the period has its own page, the Mercury Mahadasha, and the three nakshatras are Ashlesha, Jyeshtha and Revati.

The same proportion divides a nakshatra's arc: in the Nakshatra Sub-Lord calculator Mercury's sub is 113.33 minutes of arc wide in every nakshatra, 13 degrees 20 minutes times 17/120. How the sub-periods divide covers the levels below.

What the texts expect of the period

BPHS Ch. 47 Sl. 5-6 gives the test for every Dasha: favourable if at its start the lord is in the Lagna, exalted, in its own or a friendly sign; unfavourable in the 6th, 8th or 12th, in debilitation or in an enemy's sign. Sl. 62-65 then describe the Dasha of a well-placed Mercury (exalted, in its own or a friend's sign, or in the 11th, 5th or 9th): wealth, reputation, better knowledge, favour from the government, happiness at home and profit in business, in full if Mercury is aspected by a benefic, sits in the 9th or rules the 10th. Sl. 66-70 give the reverse for a Mercury joined to a malefic or placed in the 6th, 8th or 12th: trouble with authority and kin, dependence on others, travel abroad, loss of wealth. The same slokas shape the seventeen years: gains, education and happiness at the start, recognition in the middle, a distressful last part. The disease lines there are not repeated.

BPHS Ch. 58 reads the nine sub-periods one by one, each by the sub-lord's own dignity and by its house counted from Mercury: well placed, or in an angle, a trine or the 11th from Mercury, it reads well; weak, or in the 6th, 8th or 12th from Mercury, it does not. The chapter attaches a maraka warning and a prescribed remedy to most sub-periods; neither is repeated here. Saravali's Dasa chapter, written for its own Moola Dasa scheme, agrees in outline. A favourable Mercury Dasa (Ch. 41 Sl. 37-39) brings gains through friends, business people and the king, fame, intelligence and a taste for mathematics and drawing, and its sub-periods (Ch. 42 Sl. 30-35) read well for the Sun, Jupiter and Venus and badly for the Moon, Mars and Saturn.

In the app, the dasha reading applies BPHS Ch. 47 Sl. 5-6 and grades the period good for an exalted or own-sign Mercury, neutral for a friendly or neutral sign, challenging for an enemy sign, debilitation or the 6th, 8th or 12th. Its favourable theme for Mercury is sharper communication and gains through business, education or negotiation; its testing theme is scattered focus, financial leakage and strained dealings with authority. The Vimshottari Dasha calculator finds when yours runs, and the Timing feature shows the dated windows.

Mercury in other dasha systems

The Alternate Dashas calculator shows all nine alternate systems, plus Kala Chakra, with their conditions. Numerology runs a separate clock: in the Mahadasha of Advanced Vedic Numerology Mercury rules 5 years of a 45-year cycle, and the Numerology Dasha calculator follows it. When the two clocks disagree, the disagreement is itself the signal.

Transits: fast, uneven, and three times a year backward

Mercury's transit is the least regular of the visible planets'. This app labels each Mercury transit as lasting about 30 days, the figure in its source. In the engine's own positions for 1950-2049 a continuous stay in one sign ran from a single day to 69 days, with a median just under 19; the long stays are the ones that contain a retrograde. For 2026 the engine gives:

For the transit reading, this app counts the transiting planet's sign from your natal Moon sign and applies the benefic rule of its source (Kannan's transit chapter, cited in the engine) to Mercury: favourable in the 2nd, 5th, 7th, 9th and 10th, and in the 11th as for every planet; indifferent in the 3rd and 6th; testing in the 1st, 4th, 8th and 12th. Mercury in the 4th from the Moon is also flagged as one of that source's intensified combinations. The Gochar calculator shows Mercury's current house from your Moon and whether it is retrograde. The app's daily reading does not use Mercury at all; it reads the transiting Moon and Sun.

Wednesday, the hora and the divisions

Saravali Ch. 7 Sl. 1-3 gives the weekdays to the seven grahas in order from the Sun, which makes Wednesday Mercury's, and gives the first hora after sunrise to the weekday's lord. The Hora calculator builds that sequence, so every Wednesday opens in Mercury's hora, and the Choghadiya calculator opens Wednesday's daytime on Labh, the slot it assigns to Mercury and rates good. Saravali Ch. 7 Sl. 5-6 gives the use: an undertaking about some house goes better on the weekday or in the hora of that house's lord. For the houses where Gemini and Virgo fall in your chart, Wednesday and Mercury's hora are the ones the text means. The app's Muhurat scoring counts Wednesday among its favoured weekdays for a business launch, a new job, an investment and a marriage.

In the divisional charts Mercury has two fixed roles. BPHS Ch. 7 Sl. 13-16 says some grahas show their effects in the Sun's Hora and others in the Moon's, and that Mercury is effective in both; the Hora (D2) calculator gives the split. In the Trimshamsa, BPHS Ch. 6 Sl. 27-28 gives Mercury seven degrees of every sign, 18 to 25 degrees in odd signs and 5 to 12 in even ones, which the Trimshamsa (D30) calculator applies.

Mercury and the number 5

Advanced Vedic Numerology's table of numbers and planets gives 5 to Mercury, and this app's numerology engine names Mercury as the ruler of Mulank 5, which it calls the Explorer. The link is a mapping, not a calculation from the chart: a Mulank 5 person need not have a strong Mercury. Number 5 in numerology covers that side, and the Numerology feature what the app does with it.

Checking Mercury in your own chart

1. 1.Cast the chart with the Birth Chart calculator and note Mercury's sign, degree, nakshatra and house, and the retrograde and combust flags. Its house should be the Sun's or next to it.
2. 2.Read the dignity off the sign table. In Virgo, note the degree: under 15 is exaltation in every source, 15 to 20 Moolatrikona, and past 20 own sign, in the texts and in this app's dignity label alike.
3. 3.See where the lord of Mercury's sign sits. Within three signs either side, but not in the same sign, it is a temporary friend by BPHS Ch. 3 Sl. 56, which can move the grade one step.
4. 4.Find the two houses Mercury rules from your Lagna in the BPHS Ch. 34 table, and whether the Yoga Karaka panel on your Kundali lists it.
5. 5.Note who shares Mercury's house and who aspects it: any planet in the 7th from it, Mars when Mercury is 4th or 8th from Mars, Jupiter when it is 5th or 9th from Jupiter, Saturn when it is 3rd or 10th from Saturn. By the texts a malefic there changes Mercury's own nature; Jupiter's aspect is the one Saravali Ch. 26 reads well everywhere.
6. 6.Check its score in the Shad Bala calculator. Directional strength peaks in the 1st house, and a combust Mercury cannot be rated Strong there.
7. 7.Look at the yogas it forms in the Yogas calculator, its Ashtakavarga row, and its role among the Char Karakas, where BPHS Ch. 32 Sl. 3-8 ranks the seven grahas by degree and any of them can be the Atma Karaka.
8. 8.Last, timing: when Mercury's Mahadasha and Antardashas fall in the Vimshottari Dasha calculator, and where it transits now in the Gochar calculator.

Your full Kundali collects all of these in one place, and the Methodology page explains how the positions are computed.

Common misreadings

• "Mercury is a benefic, so it always helps." BPHS and Saravali both make it a malefic when it joins one, and Bhrigu Sutras extends that to a malefic aspect and to combustion. This app does not apply the conversion, so its benefic label for Mercury is the starting point, not the verdict.
• "A combust Mercury is a ruined Mercury." Mercury is combust on 41.0 per cent of days by this app's orb and on a quarter of days even by Bhrigu Sutras' 8.5 degrees. The texts weaken a combust planet; Saravali Ch. 15 Sl. 4 still gives a largely favourable reading for the Sun and Mercury together.
• "Mercury retrograde is a rare bad omen." It happens about three times a year for three weeks, and Saravali counts a retrograde benefic as strong. What BPHS attaches to it is a reversal in the order a Dasha delivers its results.
• "Exalted is exalted." Mercury's exaltation sign is also its own sign and holds its Moolatrikona; the texts read 4, 17 and 25 degrees of Virgo as three different states. And an exalted Mercury that is combust can score Weak in this app's Shad Bala.
• "The Sun aspects my Mercury" or "Venus opposes it." Neither can happen: Mercury stays within one sign of the Sun, and Venus within three signs of Mercury.
• "Mercury in Virgo gives me Bhadra Yoga." It needs Mercury in an angle as well, which only the four dual Lagnas allow, and the engine's rule is met about one time in eighteen.
• "Mercury spends a month in each sign." Its stays ran from a day to 69 days in the engine's century of positions. The 30-day figure the app prints is a label from its source, not a measurement.
• "Mercury Mahadasha means seventeen good years for business." BPHS Ch. 47 makes the outcome depend on Mercury's sign, house, company and aspects, and describes a period that opens well and closes with difficulty.

Related pages

The other grahas: the Sun, the Moon, Mars, Jupiter, Venus, Saturn, Rahu and Ketu. The houses Mercury is most tied to: the 1st house, where it gains directional strength, and the 10th, its house-karaka role in BPHS. Every book cited here is listed on the Sources page.

Is Mercury a benefic or a malefic in Vedic astrology?

A benefic by default, and the one graha whose label depends on company. BPHS Ch. 3 Sl. 11 and Ch. 34 Sl. 8-10 and Saravali Ch. 4 Sl. 9 make it a malefic when it joins a malefic. By house lordship BPHS Ch. 34 also calls it malefic for Aries, Cancer, Leo, Scorpio and Pisces Lagnas and auspicious for Virgo, Libra and Capricorn.

Where is Mercury exalted and debilitated?

Exalted in Virgo, deepest at 15 degrees; debilitated in Pisces, deepest at 15 degrees (BPHS Ch. 3 Sl. 49-50). It owns Gemini and Virgo. BPHS Sl. 51-54 divides Virgo into exaltation (0 to 15), Moolatrikona (15 to 20) and own sign (20 to 30), and this app's dignity label follows the same split.

Which planets are Mercury's friends and enemies?

Friends: the Sun and Venus. Enemy: the Moon. Neutral: Mars, Jupiter and Saturn. BPHS Ch. 3 Sl. 55 derives this from Virgo, and Saravali Ch. 4 Sl. 28-29 and Bhrigu Sutras state it directly. In a given chart BPHS Sl. 56-58 then adjusts each relationship by where the two planets sit.

Is a combust Mercury bad?

It is weakened, and it is common. Saravali Ch. 5 and Ch. 36 treat combustion as a damaged state, and this app removes a combust planet's position strength in Shad Bala. But Mercury is combust on 41.0 per cent of days by the app's 14-degree orb, so the flag alone separates few charts. It does not erase Mercury's houses or lordships.

What does a retrograde Mercury mean in a birth chart?

In the texts used here, mostly strength: Saravali Ch. 4 Sl. 36 and Ch. 5 Sl. 39 count a retrograde benefic as strong, and this engine adds a point of motional strength. BPHS Ch. 47 Sl. 3-4 adds that a retrograde Dasha lord gives its results in reverse order. Mercury was retrograde on 19.2 per cent of days in the engine's century of positions.

How long is the Mercury Mahadasha, and how do I know when mine runs?

Seventeen years in Vimshottari (BPHS Ch. 46 Sl. 15). When it runs depends on your Moon's nakshatra at birth; the Vimshottari Dasha calculator finds it from your birth date.

What is Bhadra Yoga?

Mercury's Panchamahapurusha yoga: Mercury in Gemini or Virgo and in the 1st, 4th, 7th or 10th house (BPHS Ch. 75 Sl. 1-2; Saravali Ch. 37 Sl. 2). Only Gemini, Virgo, Sagittarius and Pisces Lagnas can have it. The texts read it as learning, command of the shastras and an independent nature.

What is Budhaditya Yoga, and does the app show it?

It is the name later authors give to the Sun and Mercury in one sign; Advanced Predictive Astrology uses it, and Saravali Ch. 15 Sl. 4 gives the pair's reading without the name. This app does not list it. In the engine's positions the two shared a sign on 51 per cent of days, so on its own it distinguishes very little.

Which house is best for Mercury?

The commentary in Bhrigu Sutras finds its authorities agreed on the 10th and the 11th, and reads the 9th as very beneficial. For directional strength the answer is the 1st (BPHS Ch. 3 Sl. 35-38). Sign, company and aspects still apply in every house.

Does the app suggest remedies for a weak Mercury?

No. BPHS Ch. 58 prescribes recitations and charity for some sub-periods and Bhrigu Sutras lists a gem; this app carries no remedies, gemstones or rituals for any placement.