Choghadiya cuts the day into eight parts and the night into eight more, and gives each part one of seven names. Three of those names are treated as auspicious, three as inauspicious, and one is argued about. The tool above computes all sixteen windows for your city.
It does two things differently from the other calculators. It works the names out from a rule rather than looking them up, which is what lets it be right about the night. And it marks the windows that Rahu Kaal, Gulika or Yamaganda cancel, which across a week accounts for a third of the good daytime ones.
The seven names
Each belongs to a planet, and the planet is what the name is really about.
| Choghadiya | Lord | Standing | Conventional use |
|---|---|---|---|
| Amrit | Moon | Auspicious | Treated as the best of the seven. Anything. |
| Shubh | Jupiter | Auspicious | Ceremonies, religious rites, beginnings. |
| Labh | Mercury | Auspicious | Business, trade, study. The name means gain. |
| Char | Venus | Disputed | Travel, movement, vehicles. The name means moving. |
| Udveg | Sun | Inauspicious | Avoided, except for government and official work. |
| Kaal | Saturn | Inauspicious | Avoided, except for money matters and accumulation. |
| Rog | Mars | Inauspicious | Avoided, except for confrontation and litigation. |
Note that the three inauspicious ones each carry a sanctioned exception. That is a real part of the tradition rather than a loophole: Kaal is Saturn's, and Saturn is associated with accumulation, so a window nobody wants for a wedding is the window some traditions specifically want for putting money away.
Char is genuinely contested and this page says so instead of picking a side. Drik Panchang and ShubhPanchang call it neutral. AstroSage, Prokerala, mPanchang and ordinary Gujarati almanac practice count it as a fourth auspicious one. Gujarati sources often call it madhyam, medium. Every source does agree on what it is for: movement. If you are choosing a time to set out on a journey, the disagreement does not affect you.
The rule, which almost nobody states
The names are not arbitrary and they are not a table to be memorised. They come out of the Chaldean order of the planets, arranged slowest to fastest, which is the same ordering that produces the planetary hours:
Saturn, Jupiter, Mars, Sun, Venus, Mercury, Moon
Substituting each planet's choghadiya gives the ring this page actually walks:
Kaal, Shubh, Rog, Udveg, Char, Labh, Amrit
Now the day. Every weekday has a planetary lord, and the day's first choghadiya is always the one belonging to that lord. Sunday is the Sun's, so Sunday opens on Udveg. Monday is the Moon's, so it opens on Amrit. Tuesday is Mars, so Rog. Wednesday Mercury, so Labh. Thursday Jupiter, so Shubh. Friday Venus, so Char. Saturday Saturn, so Kaal. From there you walk the ring forward one step per window, and because there are eight windows over a seven-name ring, the eighth repeats the first.
That is the same logic as the first planetary hour of a day belonging to that day's lord. Choghadiya is not a separate invention; it is the hora machinery applied to eighths instead of twelfths.
Work one through by hand to see how little there is to it. Take a Wednesday. Wednesday belongs to Mercury, and Mercury's choghadiya is Labh, so the first daytime window is Labh. Step forward one place in the ring and Mercury gives way to the Moon, so the second is Amrit. The ring has run out at that point and wraps to the start, so the third is Kaal, Saturn's. Then Shubh, then Rog, then Udveg, then Char, and the eighth returns to Labh because eight windows over seven names must repeat one. That is the whole Wednesday daytime row, produced from one fact about Wednesday.
There is a second pattern worth noticing, because it is a useful check on any table you are handed. The weekday openings do not advance by one place per day; they advance by three. Sunday opens at Udveg, Monday three places further at Amrit, Tuesday three further again at Rog, and so on all the way round, with Saturday's Kaal sitting three places before Sunday's Udveg so the week closes. Three is not arbitrary either: a day holds twenty-four planetary hours, and twenty-four leaves a remainder of three when divided by seven, which is the same arithmetic that makes the days of the week fall in the order they do rather than in Chaldean order.
Where every other calculator goes wrong
The night does not continue the day's walk.
If it did, you would step one place further along the ring at sunset and keep going. It does not. The night advances five places per window, which means the night runs through a completely different cyclic order of the same seven names:
| Cycle | |
|---|---|
| Day | Udveg → Char → Labh → Amrit → Kaal → Shubh → Rog |
| Night | Shubh → Amrit → Char → Rog → Kaal → Labh → Udveg |
Those two are not rotations of one another. You cannot get from one to the other by starting at a different place.
Reuse the day cycle for the night and you get the right name in the first window and the wrong name in the remaining seven, on every one of the seven weekdays.
The reason this survives review is that the wrong answer is not obviously wrong. Walk Thursday's night with the day cycle and you produce Monday's daytime row, exactly. It looks like a real choghadiya row, because it is one. It just belongs to a different day.
This is a live bug in at least one published npm package, and it was the error in this project's own first draft. Establishing which of the two orders was correct took a sweep of five independent lines of evidence: the major panchang publishers, the generative rule, live dated tables cross-checked across two engines for seven consecutive days, the regional almanac literature, and fourteen open-source implementations. Three separate attempts were then made to disprove the result. All 112 slots were confirmed against four publishers with no mismatch.
The night's odd step is forced, not chosen
Here is the part that convinced me the tradition is coherent rather than sloppy.
Ask the sequence to close the week. Step once across sunset from the last day window into the first night window. Step seven times through the night. Step once more across sunrise into the next day's first window. That last window has to be the next weekday's opening name, which sits exactly three places along the ring, because weekday lords advance three places at a time in this ordering.
So nine steps of size s must equal three, modulo seven:
9s ≡ 3 (mod 7), which reduces to 2s ≡ 3, whose only solution among 0 to 6 is s = 5.
Five is the unique step that makes the week join up. The night's apparently arbitrary reshuffle is the only one that works. Nothing else lets you walk from Sunday sunrise all the way round to the following Sunday sunrise and arrive where you started.
What this page adds: the cancellations
Choghadiya on its own is an incomplete answer, and most sites present it as though it were the whole thing.
Rahu Kaal, Yamaganda and Gulika Kalam are also eighths of the daylight, selected by weekday. So each of them lands exactly on one choghadiya window, never straddling two. And the convention is that an overlapping veto period cancels the window whatever its name. Drik Panchang describes work begun in such a window as unfruitful, and Prokerala states that the auspicious set holds except where vaar vela, kaal vela or kaal ratri overlap it.
Since this site already computes Rahu Kaal, Gulika and Yamaganda exactly, it intersects the two tables. The result is more consequential than it sounds:
| Weekday | Good daytime windows | Cancelled | Left clear |
|---|---|---|---|
| Sunday | Labh, Amrit, Shubh | none | all three |
| Monday | Amrit, Shubh, Labh | none | all three |
| Tuesday | Labh, Amrit, Shubh | Amrit by Gulika, Shubh by Rahu Kaal | Labh only |
| Wednesday | Labh, Amrit, Shubh | Amrit by Yamaganda, Shubh by Gulika | Labh |
| Thursday | Shubh, Labh, Amrit | Shubh by Yamaganda, Amrit by Rahu Kaal | Labh |
| Friday | Labh, Amrit, Shubh | Labh by Gulika | Amrit, Shubh |
| Saturday | Shubh, Labh, Amrit | Labh by Yamaganda | Shubh, Amrit |
Across the week that cancels eight of the twenty-four auspicious daytime windows, a third of them, and it is very unevenly spread. Sunday and Monday lose nothing at all. Tuesday, Wednesday and Thursday each lose two, and Tuesday is left with a single uncancelled auspicious window in the entire daytime.
If you have ever been told to use a good choghadiya and separately been told to avoid Rahu Kaal, this table is why those two instructions sometimes leave you with almost nothing. Nobody computes the intersection for you, so the conflict shows up only when you try to follow both.
One honest limit. Some publishers apply a further overlay called Vaar Vela, Kaal Vela and Kaal Ratri. Those are a genuine additional veto layer, but the placements could not be established for every weekday from the sources available, so this page does not draw them. Omitting a layer and saying so is better than drawing it from guesses, and the windows it would mark are additional to what is shown rather than replacing anything.
Why the boundaries move but the names never do
The names depend on the weekday and on nothing else. Not the date, not the season, not any planetary position. A Tuesday in February and a Tuesday in August carry the identical sixteen names in the identical order. No choice of ayanamsa can move them, because no ayanamsa enters the calculation.
What moves is where the windows fall, and that comes entirely from sunrise and sunset.
Because a day window is one eighth of the daylight and a night window one eighth of the darkness, the two are only equal at the equinoxes. In Delhi in mid-August a day window runs about 99 minutes while a night window runs about 81. At the December solstice that reverses. Near the equator the gap narrows: Chennai's day and night windows stay much closer to each other all year. Push far enough north and the asymmetry becomes extreme, and above the Arctic Circle the scheme stops being meaningful at all, which is why this page reports an error rather than a number for a latitude where the Sun does not rise.
Why another site gives you different times
The names should match any correct source exactly, since they depend only on the weekday. If the names differ, one of the two is wrong, and given how common the night error is, it is worth checking whether the disagreement is in the night half.
The times can legitimately differ for the usual reasons:
A different sunrise definition. The civil convention uses the Sun's upper limb corrected for refraction; some traditional panchangs use the geometric centre of the disc. Three to five minutes at Indian latitudes, and each window inherits a share of it.
Different coordinates for your city, or a different city entirely. Sunrise in Kolkata is about forty minutes earlier than in Mumbai.
A hard-coded day. Several open-source implementations assume the day runs 06:00 to 18:00 and divide that. Their names are right and their times are wrong everywhere except twice a year.
The weekday boundary. The Hindu day runs sunrise to sunrise, so a moment after midnight but before sunrise belongs to the previous weekday and takes its sequence. A night window at 02:00 belongs to the previous day's night, not to the new calendar date. Using the calendar weekday instead produces a table that is wrong for the whole night.
What this page will not tell you
It will not tell you that your business will fail if you sign during Rog.
What is computed here is a division of daylight and darkness into eighths, and a naming rule that is fully specified, entirely checkable and rather elegant: the same planetary ordering that gives us the names of the days of the week, applied at a finer grain, with a step size the week's own closure forces. That much is mathematics and history, and it is worth getting right.
Whether the names carry any consequence is a separate question, and one this page takes no position on. What it will not do is present three good windows without mentioning that on a Tuesday two of them are cancelled.