Rahu Kaal

What this page adds to the Rahu Kaal result

The calculator above gives one window for one day and a short note about how the day was measured. This long read goes underneath that answer. It sets out where the weekday table comes from and where it does not, shows the arithmetic the engine performs to turn a sunrise into a window, runs the engine for real dates and places so you can see how far the window moves, and explains each field the result can carry. It also says plainly what Rahu Kaal is not: it is not a reading of your chart, it is not a prediction, and it is not found in the classical texts this app holds.

Rahu Kaal belongs to the family of day-reckoning tools that need no birth details. Its nearest relatives here are the choghadiya calculator, the hora timings and the daily panchang. All four are cut from the same three instants - sunrise, sunset and the next sunrise - and all four are computed in a single pass by one engine function, so their windows can never disagree with one another.

Where Rahu Kaal comes from, and what the classical texts leave unsaid

Rahu in the source texts

Brihat Parashara Hora Shastra lists nine grahas in Ch. 3 Sl. 10: the Sun, the Moon, Mars, Mercury, Jupiter, Venus, Saturn, Rahu and Ketu. The next sloka sorts them, placing Rahu and Ketu - which the translation glosses as the ascending and descending nodes of the Moon - among the malefics, together with the Sun, Saturn, Mars and the decreasing Moon. Sl. 30 describes Rahu as smoky in appearance, windy in temperament and intelligent, and adds that Ketu is akin to him. That is the classical character behind the name; the learn page on Rahu follows it through the rest of the text.

What matters for a daily window is something the same chapter makes visible by omission. Seven grahas own a weekday; Rahu and Ketu do not. The week has no day of Rahu. A scheme that wants to give Rahu a share of time therefore cannot hand him a day and has to hand him a part of each day instead. Rahu Kaal is exactly that kind of share: one eighth of every daytime, in a position that changes with the weekday.

The honest gap

None of the classical texts in this app's source library names Rahu Kaal or gives its weekday table. BPHS does not, Saravali does not, and the horary text Daivajna Vallabha does not. The table this calculator uses comes from the living panchang tradition, as published by Drik Panchang, whose statement of the rule is quoted in the engine's own source code: Monday takes the 2nd period of the day, Saturday the 3rd, Friday the 4th, Wednesday the 5th, Thursday the 6th, Tuesday the 7th and Sunday the 8th. The sources page lists what each feature rests on, and for Rahu Kaal that entry is a published almanac convention, checked against published times, and not a sloka.

The same holds for what the window is supposed to mean. The custom, as this page's introduction says, is to leave the window alone for starting something new. No text in the corpus states that rule, lists the activities it covers, or describes a consequence for ignoring it, so this page does not either. Where the sources are silent, the description stops.

What BPHS does describe: the day in eight parts

Although Rahu Kaal itself is absent, the machinery it runs on is unmistakably classical. BPHS Ch. 3 Sl. 66-69 gives the calculation of Gulik and its companions in these terms: divide the day duration of any weekday into eight equal parts; distribute seven of them to the seven grahas, commencing from the lord of the weekday; the eighth portion is lordless. The portion that falls to Saturn is Gulik. The Sun's portion is called Kaal, Mars's portion Mrityu, Jupiter's portion Yamaghantak and Mercury's portion Ardhaprahar. The translator's notes call these five the Kaal Velas and spell out that the remaining portions follow in the order of the weekday lords. The night is divided into eight parts as well, opening on the lord of the fifth weekday.

Two features of that passage carry straight over to Rahu Kaal. First, the unit is an eighth of the actual daytime, not a fixed number of minutes. Second, the sloka ends by saying that these durations apply differently to different places, in step with the variable lengths of day and night. A Rahu Kaal printed as the same clock time for every city and every month ignores that sentence. The table below applies the BPHS rule by hand for Saturn's and Jupiter's portions and sets them beside the Rahu Kaal table, so the relationship between the two schemes can be seen.

Three things follow from the table. On no weekday does Rahu Kaal share a part with Gulik or with Yamaghantak, so the three are separate windows. Only on Sunday does Rahu Kaal take the part BPHS calls lordless. And the Rahu Kaal column does not follow the simple backward step of the Gulik column, which is why it cannot be derived from the BPHS rule and has to be taken as its own table. This calculator returns Rahu Kaal only; it does not compute Gulik's portion or the other Kaal Velas.

The weekday table, part by part

The whole of the rule is seven numbers. In the code they sit in one constant, counted from zero, and every surface of the app that mentions Rahu Kaal reads that constant and nothing else. The table gives them as ordinary counts, with the window each produces on an even twelve-hour day and the choghadiya name that occupies the same part of the daytime.

The third column is the table most people know by heart, and it is correct only for a day that runs from exactly 6:00 AM to exactly 6:00 PM. The first two columns are the rule itself.

From sunrise to a window: the exact steps

When you give a place, the calculator follows a short, fixed sequence. Nothing in it depends on who is asking.

1. 1.The place is resolved to a latitude, a longitude and an IANA time zone. If you typed a date, it is read as that calendar date at that place; if you left the date blank, the day is today at that place.
2. 2.Local midnight opening that date is found in the place's own time zone, with the zone's offset looked up at that instant so that a daylight-saving change is honoured.
3. 3.Sunrise and sunset for that date are computed with the method in Meeus, Astronomical Algorithms, ch. 15: the Sun's hour angle at the standard altitude of -0 deg 50 min gives a first estimate, which is then refined until the step is under a tenth of a second. That altitude is the usual almanac definition - the Sun's upper edge on the horizon, with average refraction.
4. 4.The span from sunrise to sunset is divided into eight equal parts. This is the same array the day choghadiya is read from.
5. 5.The weekday of that local calendar date picks one part from the table: Thursday picks the 6th, and so on.
6. 6.The start and end of that part are converted to the place's clock, rounded to the nearest minute, and printed as a range.

The night is divided too, from sunset to the next sunrise, but Rahu Kaal never reads it: in this engine Rahu Kaal is a daytime window on every weekday. The night eighths matter here only because the avoid list, described below, includes night choghadiya slots. The methodology page describes the astronomy this app uses in general, including the fact that it is the app's own implementation of published formulas.

The arithmetic for one real day

The rules document carries a fully worked case that the test suite pins. Mumbai, Monday 1 January 2024: sunrise 07:11:35 and sunset 18:11:54 IST. The daylight is 660.32 minutes, so one eighth is 82.54 minutes. Monday takes the 2nd eighth, which begins one eighth after sunrise and ends two eighths after it: 07:11:35 plus 82.54 minutes is 08:34:07, and 07:11:35 plus 165.08 minutes is 09:56:40. Rounded to the minute, the engine prints 8:34 AM to 9:57 AM, which is the window Drik Panchang published for that day. The memorised table would have said 7:30 to 9:00 - more than an hour early at the start and almost an hour early at the end.

A worked Rahu Kaal week for New Delhi

To show the result as the calculator returns it, the engine was run for the week of 12 to 18 October 2026 twice: once with no place, and once for New Delhi at 28.6139 N, 77.2090 E on the Asia/Kolkata clock. Mid-October is close to an equinox, so this is the season in which the fixed clock is at its best.

Take Thursday. Sunrise is 6:22 AM and sunset 5:52 PM, a daytime of about 690 minutes, so each eighth is a little over 86 minutes. Thursday's is the 6th eighth, which opens five eighths after sunrise: about 431 minutes after 6:22 AM, which is 1:33 PM. It closes one eighth later, at 2:59 PM. The fixed clock gives 1:30 to 3:00 for the same day, three minutes out at the start and one at the end.

Now look at the edges of the day. On Monday the window sits early, and the whole of the error is the late sunrise: the sunrise window starts seventeen minutes after the fixed one. On Sunday the window is the last eighth, so it ends at sunset, 5:49 PM, eleven minutes before the fixed clock's 6:00 PM. Even in the kindest week of the year, a quarter of an hour separates the two answers on some days.

How season and latitude move the window

Away from the equinoxes the gap widens, for two separate reasons. The length of the daytime changes, which changes the length of every eighth. And the sunrise itself moves, which shifts where the count begins. The engine was run for four Thursdays in 2026 at New Delhi to show both effects on the same weekday.

In June the window is 105 minutes long and ends at 3:52 PM, fifty-two minutes after the fixed table says it is over. In December it shrinks to 77 minutes. Only near the equinoxes is it the ninety minutes people expect, and even then it does not start on the half hour, because Delhi's sunrise is not at 6:00.

Place matters as much as season. India keeps one clock across roughly thirty degrees of longitude, so the Sun rises far earlier on that clock in the east than in the west. The engine was run for the same two Thursdays in five places.

On 24 December the window in Guwahati runs 12:41 to 2:00 PM and the window in Dwarka runs 2:14 to 3:35 PM. They do not overlap at all: the Guwahati window has been over for fourteen minutes before the Dwarka one begins. Both are the 6th eighth of a Thursday, and both are on the same national clock. The latitude effect shows in the Chennai and Srinagar rows: Chennai's window changes length by twelve minutes between June and December (97 against 85), Srinagar's by thirty-three (108 against 75), because the daytime varies more the further a place is from the equator.

Outside India the same rule produces larger swings. For London, the engine returns 3:07 PM to 5:08 PM on Thursday 16 July 2026, with sunrise at 5:02 AM and sunset at 9:10 PM on the Europe/London clock, which is on summer time that day. The window is 121 minutes long. On Thursday 15 January 2026 it returns 1:13 PM to 2:15 PM, a window of 62 minutes.

Reading every part of the result

The window

The headline value is a single range such as 1:33 PM to 2:59 PM. It is printed on the clock of the place you gave, or on IST when you gave none, and both ends are rounded to the nearest minute. The start is included and the end is where the next eighth begins. There is one Rahu Kaal per day; the calculator never returns two, and it never returns one at night.

The date label

The result names the day it describes, for example Thu, 15 Oct. This is worth a glance, because the weekday is the only input the table reads. With a place, the label is the calendar date at that place. Without a place it is the IST calendar date, and the weekday is taken from that same IST date, so a request made in the small hours in India is read as the day that has already begun there.

The avoid list

Beside the window, the result carries a list titled avoid. It contains every day and night choghadiya slot whose name the choghadiya table grades as avoid - Udveg, Rog and Kaal - followed by Rahu Kaal itself as the last entry. For New Delhi on Thursday 15 October 2026 the engine returns seven entries: Rog (7:48 AM to 9:14 AM), Udveg (9:14 AM to 10:41 AM), Kaal (2:59 PM to 4:26 PM), Rog (8:59 PM to 10:33 PM), Kaal (10:33 PM to 12:07 AM), Udveg (1:41 AM to 3:15 AM) and Rahu Kaal (1:33 PM to 2:59 PM). The list is not sorted by time: day slots come first, then night slots, then Rahu Kaal. The entries after sunset belong to the night that follows the day, so the 1:41 AM slot is in the small hours of Friday. The choghadiya page explains the seven names and their grades.

The daylight block: four cases

Every result says how the day was measured. This is never left out, because a fixed-clock window mistaken for a sunrise one is the exact error the note exists to prevent. There are four cases, and it is worth knowing which one you are looking at.

In the three fixed cases the sunrise and sunset fields are empty by design. Six o'clock is not a sunrise and the result does not print it as one. The last case is rare but real: for Tromso on Thursday 18 June 2026 the engine reports that the Sun does not both rise and set on that date and the next, and returns 1:30 PM to 3:00 PM on the Europe/Oslo clock as an even division.

When Rahu Kaal and a good choghadiya are the same minutes

Because Rahu Kaal and the day choghadiya are read from one array of eight parts, Rahu Kaal always coincides with exactly one choghadiya slot, to the minute. The table earlier on this page shows which. On five weekdays the two systems agree: the slot under Rahu Kaal is Kaal, Rog or Udveg, which the choghadiya table already grades as avoid. On two they disagree. Tuesday's Rahu Kaal falls on Shubh, graded good, and Thursday's falls on Amrit, the one name graded excellent.

The Thursday case is visible in the New Delhi example. The day choghadiya for 15 October 2026 lists Amrit at 1:33 PM to 2:59 PM, and Rahu Kaal for the same day is 1:33 PM to 2:59 PM. The two traditions were built separately and nothing reconciles them: one table calls the slot the best of the day, the other says to leave it. This is why the avoid list above does not contain Amrit as a name and still contains its minutes, as the Rahu Kaal entry.

The app handles the conflict the same way everywhere, by letting Rahu Kaal override and by saying that it has done so. On the Muhurat page, the day strip colours the slot as avoid and labels it with both names, so a Thursday afternoon reads Amrit, Rahu Kaal and not simply Amrit. In the weekly plan, the code that picks each day's best choghadiya window first removes the slot whose window equals Rahu Kaal, so the plan cannot recommend as best a window it also lists under avoid. If you use the two calculators side by side, apply the same reading: a good or excellent choghadiya that sits under Rahu Kaal is a contested slot, not a clean one.

Where else the app reads Rahu Kaal

In the muhurat score

The muhurat calculator scores ninety-minute candidate windows for an activity against your chart. Each score starts from a base of 34 and moves with several independent factors: the Moon's nakshatra, the Moon's house from your natal Moon, the tithi, the weekday, your Personal Day. A window that overlaps Rahu Kaal at all loses 25 points and carries the reason line that it overlaps Rahu Kaal and is best avoided. Since a window is called excellent from 78 and good from 62, a 25-point deduction is usually enough to drop it a band.

Two details of that scoring are easy to miss. The first is that it uses the fixed 06:00 to 18:00 IST grid, not sunrise. A muhurat is scored for an activity whose location is unknown - your birth place is where you were born, not where you will sign a lease - so there is no sunrise to cut the day from, and the windows it offers are printed in IST on that same grid. The second is which windows can be hit. The scorer samples three starts per day: 6:40 AM, 9:15 AM and 3:30 PM. Set against the fixed table, the early window overlaps Rahu Kaal on Mondays; the mid-morning window overlaps it on Fridays and Saturdays; the afternoon window overlaps it on Tuesdays and Sundays. On Wednesdays and Thursdays none of the three sampled windows touches Rahu Kaal, so the deduction never applies on those days.

In the daily and weekly views

The daily guidance and timing features sit on the same engine, and the career and money calculator builds its weekly plan from it, carrying each day's Rahu Kaal alongside the best window it picked. Every one of these reads the single weekday table, so they cannot disagree about which part of the day is Rahu Kaal.

Limits, and what the result is sensitive to

• It does not read you. No birth date, time or place goes in, so two people in one town get the same window. Anything personal - a dasha, a transit, a house - lives elsewhere, for example in the Vimshottari dasha calculator or the transit (gochar) calculator.
• It has no birth-time sensitivity at all, which makes it one of the few results on this site that an uncertain birth time cannot disturb. Its sensitivity is to place and date instead.
• It is as good as the place you give. The tables above show windows in two Indian cities that do not overlap on the same day. A window computed for the nearest metro is not the window for a town several hundred kilometres east or west of it.
• Sunrise is computed for sea level and a flat horizon. The code deliberately leaves out elevation and local terrain, as almanacs do, along with two corrections that are each well under a second. A hill to the east will delay the Sun you actually see; the calculation does not know about it.
• Times are rounded to the minute. A boundary that falls within a few seconds of the half-minute can print one minute differently from another almanac, as one of the pinned anchors shows: for Mumbai on Thursday 4 January 2024 the computed end is 15:28:27, so it prints 3:28 PM against a published 3:29 PM.
• Other almanacs may differ by a minute or two for honest reasons: slightly different coordinates for the same city, or a different definition of sunrise. The rules document notes that Drik Panchang's stated coordinates for Mumbai move every boundary by one or two seconds against the app's bundled ones.
• It is a daytime rule. The engine defines Rahu Kaal on the day eighths only and returns nothing for the night.
• It makes no claim about outcomes. The result is a window and a disclosure of how it was measured. It does not say what will happen inside the window, and no source this app holds does either.

How Rahu Kaal fits with the rest of the site

Rahu Kaal is the simplest member of the day-reckoning group and makes most sense read with the others. The choghadiya grades all sixteen parts of the day and night, where Rahu Kaal marks one. The hora cuts the same daytime into twelve parts and gives each a planetary lord, starting from the weekday's own - the same starting point BPHS uses for the eight-part division. The panchang adds the lunar side of the day, the tithi and paksha, read at the same computed sunrise, and the Moon phase calculator shows the elongation behind it.

For a decision that deserves more than a daily window, the muhurat calculator weighs Rahu Kaal as one factor among several and shows its reasons. BPHS itself, in Ch. 89, asks for rites to be performed in a muhurta when the Moon and the stars are favourable and on a day free of Rikta-Bhadra Dosha - a reminder that the classical idea of a good time was never a single rule. And for a question about a moment that has already arrived, the Prashna feature reads the chart of the question itself.

Rahu Kaal should not be confused with the things in a birth chart that also carry Rahu's name. A Rahu Mahadasha is an eighteen-year period in the Vimshottari scheme, fixed by the Moon's nakshatra at birth. Kaal Sarp Dosha is a question about whether all seven planets lie on one side of the Rahu-Ketu axis in a chart, which the article Kaal Sarp Dosha explained treats as geometry. Rahu's house in your chart is covered from Rahu in the 1st house onward. None of these has anything to do with the daily window: Rahu Kaal uses no planetary position, not even Rahu's own. It is a division of the daytime by the weekday, and that is all it is.

Questions people ask about Rahu Kaal

Is Rahu Kaal the same time every day?

No. It is a different eighth of the daytime on each weekday - the 2nd on Monday, the 7th on Tuesday, the 5th on Wednesday, the 6th on Thursday, the 4th on Friday, the 3rd on Saturday and the 8th on Sunday. Within one weekday it also moves through the year, because the eighths are measured from sunrise to sunset. For New Delhi the engine gives a Thursday window of 2:07 PM to 3:52 PM in mid-June 2026 and 1:38 PM to 2:55 PM in late December.

Why does this calculator disagree with the table I memorised?

The memorised table - Monday 7:30 to 9:00, Tuesday 3:00 to 4:30 and so on - assumes sunrise at exactly 6:00 AM and sunset at exactly 6:00 PM. That is what this calculator returns when you give no place, and it says so in the note. With a place it measures from the real sunrise, so the start and the length both change. For Mumbai on Monday 1 January 2024 the sunrise-based window is 8:34 AM to 9:57 AM, against 7:30 to 9:00 from the table.

Is Rahu Kaal always ninety minutes long?

Only when the daytime is exactly twelve hours. The window is one eighth of the daytime, so it is longer in summer and shorter in winter. The engine's New Delhi figures for 2026 are 105 minutes on 18 June and 77 minutes on 24 December; for London they are 121 minutes on 16 July and 62 minutes on 15 January.

Do I need my birth details for Rahu Kaal?

No. The calculation reads a date and, ideally, a place. It uses nothing about the person asking, so the window is the same for everyone in the same town on the same day. The place it wants is where you are on that day, not where you were born.

Which classical text gives the Rahu Kaal table?

None of the texts this app holds. BPHS Ch. 3 Sl. 66-69 describes dividing the day into eight equal parts and assigning them to the grahas from the weekday lord, which gives Gulik and four related portions, but it does not mention Rahu Kaal. The weekday table used here is the published panchang convention, quoted in the engine's source and checked against published times for all seven weekdays. The sources page sets out what each feature rests on.

Is Rahu Kaal the same as Gulika Kaal or Yamaganda?

No. Applying the BPHS rule by hand, Gulik is Saturn's portion of the eight-part day and Yamaghantak is Jupiter's, and on no weekday does either fall in the same part as Rahu Kaal. On a Thursday, for instance, Yamaghantak is the 1st part, Gulik the 3rd and Rahu Kaal the 6th. This calculator returns Rahu Kaal only.

What if Rahu Kaal falls on an Amrit or Shubh choghadiya?

It does so every week: Thursday's Rahu Kaal is the Amrit slot and Tuesday's is the Shubh slot, because both systems are read from the same eight parts of the day. The two tables simply disagree about those minutes. This app lets Rahu Kaal take precedence and shows both names, so the Muhurat page labels the slot with the choghadiya name and Rahu Kaal together, and the weekly plan will not pick that slot as the day's best window.

What does it mean if the result shows no sunrise time?

It means the window was not measured from a sunrise. Either no place was given, or the place could not be found, or the Sun does not both rise and set there on that date. In each case the day is taken as a fixed 06:00 to 18:00 and divided evenly, and the note under the result says which of the three applied. Enter or correct the place to get a sunrise-based window.