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Tithi Calculator
Find the Hindu tithi — the lunar day — for any date, time and place. This free tithi calculator shows the tithi name and number, the paksha, and the separate tithi at sunrise that is used to fix festival dates, all worked out from the real positions of the Sun and Moon.
| Tithi | — |
| Paksha | — |
| Tithi at sunrise (06:00 local) | — |
| Moon − Sun elongation | — |
| Sun longitude (tropical) | — |
| Moon longitude (tropical) | — |
Festivals in the Hindu calendar are fixed by the tithi running at sunrise, which is why this tool also shows the sunrise tithi.
How to use this calculator
- Enter the date you want to check — today, a festival date, or any day in the past or future.
- Enter the time of day you care about. The tithi can change at any hour, so the time matters.
- Select the timezone of the place. IST is selected by default.
- Press Find the tithi.
- Read the current tithi and paksha, and the separate sunrise tithi — the one used to fix most festival dates.
How the tithi is calculated
A tithi is a lunar day. It is defined purely by the angle between the Moon and the Sun: every time the Moon moves 12 degrees further away from the Sun (measured along the zodiac), one tithi ends and the next begins. A full cycle of 30 tithis — one lunar month — therefore covers 360 degrees of elongation, from new moon (Amavasya) back to new moon.
The first 15 tithis, while the Moon waxes, form the Shukla Paksha and end with Purnima, the full moon, at exactly 180 degrees of elongation. The next 15 form the Krishna Paksha as the Moon wanes, ending with Amavasya at 360 degrees. Because the Moon's speed varies, a tithi is not a fixed length: it averages about 23 hours 37 minutes but can be as short as 19 hours or as long as 27. This is why a tithi sometimes covers two sunrises (and its festival is skipped in some traditions) or ends between two sunrises (and is repeated).
Traditionally, the tithi that counts for a festival is the one running at sunrise. This calculator approximates that sunrise value by computing the tithi at 06:00 local time on the chosen date, which is close to sunrise for most of India for most of the year. A note on accuracy: this tool uses a compact, standard set of astronomical formulas. The Moon's position is accurate to within about half a degree, so if the Moon sits very close to a boundary, exact ephemeris software or a printed panchang may place the result in the neighbouring nakshatra or rashi. For important religious or personal decisions, cross-check with a detailed panchang.
| No. | Shukla Paksha (waxing) | Krishna Paksha (waning) |
|---|---|---|
| 1 | Pratipada | Pratipada |
| 2 | Dwitiya | Dwitiya |
| 3 | Tritiya | Tritiya |
| 4 | Chaturthi | Chaturthi |
| 5 | Panchami | Panchami |
| 6 | Shashthi | Shashthi |
| 7 | Saptami | Saptami |
| 8 | Ashtami | Ashtami |
| 9 | Navami | Navami |
| 10 | Dashami | Dashami |
| 11 | Ekadashi | Ekadashi |
| 12 | Dwadashi | Dwadashi |
| 13 | Trayodashi | Trayodashi |
| 14 | Chaturdashi | Chaturdashi |
| 15 | Purnima | Amavasya |
Worked example
Check 25 January 2024 at 12:00 IST — the values the calculator starts with.
Step 1: at noon that day the Sun's tropical longitude is about 304.77 degrees and the Moon's is about 119.31 degrees, so the elongation — Moon minus Sun, wrapped into 0–360 — is 174.55 degrees.
Step 2: divide by 12 — 174.55 ÷ 12 = 14.5, so we are in the 15th tithi.
Step 3: tithi 15 of the Shukla Paksha is Purnima, the full-moon tithi — and indeed 25 January 2024 was observed as the full moon day (Paush Purnima).
Step 4: the sunrise check at 06:00 the same morning gives the same Purnima, so the festival tithi and the noon tithi agree for this date.
FAQ
What is a tithi?
A tithi is a lunar day in the Hindu calendar. It begins and ends not at midnight or sunrise but whenever the Moon has moved 12 degrees away from the Sun along the zodiac. Thirty tithis make one lunar month, fifteen in the waxing Shukla Paksha and fifteen in the waning Krishna Paksha.
Why does the tithi change at odd times of day?
Because a tithi is tied to the Moon's motion, not to the clock. The Moon's speed changes through the month, so a tithi can last anywhere from about 19 to 27 hours and can end at any hour — morning, afternoon or the middle of the night. That is also why a tithi and a calendar date rarely line up neatly.
Why do festivals use the tithi at sunrise?
Classical panchang practice assigns each calendar day the tithi that is running at local sunrise, and most festivals are fixed by that sunrise tithi. This tool approximates the sunrise value by computing the tithi at 06:00 local time, which is near sunrise across most of India for most of the year, but a printed panchang for your exact city remains the authority.
What is the difference between Purnima and Amavasya?
Purnima is the 15th tithi of the Shukla Paksha, when the Moon is opposite the Sun (180 degrees of elongation) and appears fully lit — the full moon. Amavasya is the 30th and last tithi, when the Moon meets the Sun (360 degrees, wrapping to 0) and the night is moonless — the new moon.
Can a tithi be skipped or repeated?
Yes. If a whole tithi begins and ends between two sunrises, it never appears at a sunrise and is called a kshaya (skipped) tithi. If one tithi is running at two consecutive sunrises, it is an adhika (repeated) tithi and its festival may be observed on either day depending on tradition. Both happen because a tithi is shorter or longer than a solar day.
How accurate is this tithi calculator?
The Sun and Moon longitudes come from standard low-precision astronomical formulas; the Moon is good to about half a degree, which is roughly one hour of tithi time. If a tithi boundary falls within about an hour of the moment you enter, exact ephemeris software may disagree by one tithi — for religious observance, confirm close calls with a detailed panchang.