Birth Tithi From Date of Birth: How to Calculate It

A tithi is not a date. It is a distance: how far the Moon has pulled ahead of the Sun along the zodiac, counted in steps of twelve degrees. Your birth tithi is the step the Moon was in at the minute you were born. Two numbers decide it, the Moon’s longitude and the Sun’s, and once you have them the rest is one subtraction and one division.

The usual shortcut, looking up your birth date in a printed panchang, answers a slightly different question. A panchang names each day by the tithi running at sunrise. Through 2027, for about 31 percent of the minutes, the tithi actually running will not be the one the panchang prints for that date at New Delhi. This page gives the calculation, works it through for three births, and then takes the harder half of a Hindu date of birth: the paksha and the month name.

The Formula

Take the Moon’s longitude, subtract the Sun’s, and if the answer is negative add 360. That is the elongation. Divide it by 12 and drop the fraction: the whole number is how many tithis have been completed since the last new moon, so add one for the tithi in progress. Numbers 1 to 15 are the bright fortnight (Shukla paksha), ending with Purnima at 15. Numbers 16 to 29 are Krishna Pratipada to Krishna Chaturdashi, and 30 is Amavasya.

Both longitudes must be measured from the same zero, but it does not matter which zero. The tithi is a difference between two positions, so the ayanamsa that separates the sidereal zodiac from the tropical one cancels out of it. A Western chart’s tropical degrees give the same elongation as an Indian chart’s sidereal ones. They do not give the same month name, which is why the month section below asks for the sidereal Sun. What the formula does need is full longitudes from 0° to 360°, not degrees within a sign: 10° Taurus is 40°, 10° Capricorn is 280°.

This is the rule the site’s own panchang runs on. Applied at the printed sunrise minute, it reproduces the sunrise tithi of all 730 days of the daily panchang table for 2026 and 2027.

Where to Get the Two Degrees

The free kundli prints both. Sign in, enter the date, time and place of birth, and under the chart tiles a line reads “The Moon was at … and the Sun at … sidereal”, with each figure already a full longitude in degrees and minutes. Those two numbers are all the formula needs. A janam patri or a printed horoscope often lists the same positions as a sign and a degree within it; convert each by adding 30° for every sign before it, counting Aries as the first.

How exact must the birth time be? The elongation grows by 0.45° to 0.60° an hour, according to how fast the Moon is moving. Unless the elongation lands within 0.6° of a multiple of twelve, an hour’s error in the birth time cannot change the tithi. When it does land that close, the tithi was changing within an hour or so of the birth, and the birth time decides it.

Three Births Worked Through

The three birth times below are imaginary, chosen in early 2027 so that each shows a different case. The degrees are what the site’s ephemeris gives for those instants in IST, truncated to the minute the way the free kundli prints them, and the arithmetic is done on those printed figures.

Mid-morning, tithi unchanged since sunrise. At 10:00 on 17 January 2027 the Moon is 106.68° ahead of the Sun. Twelve goes into that eight whole times, so the birth falls in tithi 9, Shukla Navami. The panchang for the date says the same, because sunrise at New Delhi is at 07:14 and the tithi does not change in the hours between.

Small hours, before the date's sunrise. At 02:00 on 26 January 2027 the elongation is 225.82°, which puts the birth in tithi 19, Krishna Chaturthi. The panchang for 26 January 2027 lists Krishna Panchami, the next tithi, because by its 07:12 sunrise the tithi has already changed. Anyone born in the small hours should check for this: the calendar date begins at midnight, but the tithi printed against it is the one in force hours later, at sunrise.

Late evening, after the tithi changed. At 21:30 on 5 February 2027 the Moon reads 281°28′ and the Sun 292°22′. The Moon’s figure is the smaller one, so the subtraction comes out negative and 360 is added, giving 349.10°. Dividing by twelve gives 29.09: twenty-nine tithis complete, the thirtieth running, so this is Amavasya. The panchang lists 5 February 2027 as Krishna Chaturdashi, the tithi at that morning’s sunrise. The new moon tithi holds the next sunrise instead, which is why Mauni Amavasya 2027 falls on the following day.

How Often the Panchang Date Gives a Different Tithi

Sampled every ten minutes through 2027, the tithi disagrees with the sunrise tithi printed for the same date at New Delhi 31 percent of the time. Most of that disagreement comes after sunrise, not before it. Between midnight and sunrise the tithi differs from the date’s printed one 15 percent of the time; between sunrise and the following midnight it differs 36 percent of the time. The reason is simple: the longer the gap between a birth and the sunrise that named the date, the more likely a tithi change fell inside it, and a late-evening birth comes more than twelve hours after it.

Two more traps sit in the printed calendar. A tithi shorter than the time between two sunrises can begin and end without holding either, so no date in the panchang carries its name, although people are born in it. A tithi longer than a day can hold two sunrises, and then two consecutive dates carry the same name. Both are listed in kshaya and vriddhi tithis, and how long a tithi can last is measured in how many days a lunar month has.

The Paksha and the Month Name

The tithi number already gives the paksha: up to 15 is Shukla, 16 and above is Krishna. The month name takes one more step. In the amanta reckoning a month runs from one new moon to the next and takes its name from the sidereal sign the Sun was in at the new moon that opened it: Sun in Pisces gives Chaitra, Aries gives Vaishakha, and so on through Aquarius, which gives Phalguna.

The obvious shortcut, taking the Sun’s sign at birth, gets that wrong about half the time. Tested every three hours from 1950 to 2027, it named the wrong sign 49 percent of the time, because the Sun often changes sign between the new moon and the birth. A better estimate subtracts one-twelfth of the elongation from the Sun’s longitude. The elongation divided by twelve is roughly the number of days since the new moon, and the Sun moves about a degree a day, so the result is close to where the Sun stood at that new moon. Over the same 78 years the estimate was never more than 2.1° out, and it picked the wrong sign only when it landed within 2.5° of a sign boundary. Roughly one birth in six lands that close; for those, the month needs the new moon itself, from an almanac for the birth year.

In the first example the Sun stands at 272°35′, already in Capricorn, which on its own would suggest Magha. One-twelfth of 106.68° is about 8.9°, and taking that off leaves the Sun at roughly 263.7°, inside Sagittarius, well clear of its edge. So the month is Pausha, and the birth is Pausha Shukla Navami. The same check puts the other two births in Pausha too.

One adjustment remains for northern India. Almanacs that end the month at the full moon (purnimanta), the north Indian reckoning, file every dark-fortnight tithi under the next month’s name; Maharashtra, Gujarat, Goa, Karnataka, Telangana and Andhra Pradesh keep the amanta name. So the second example is Pausha Krishna Chaturthi in an amanta almanac and Magha Krishna Chaturthi in a purnimanta one, and the third is Pausha Amavasya or Magha Amavasya. The bright fortnight carries the same name in both. When someone gives you a birth tithi with a month, ask which reckoning it uses; the paksha and tithi will match, and the month may not. How the two fortnights fall through each year is set out in Shukla and Krishna paksha dates.

The rule above leaves two cases open. If the Sun has not changed sign by the next new moon, the month just ended is an adhika (extra) month and takes the same name. The site’s table of those starts in 2020; the adhik maas page lists them, and an older birth needs an almanac for its year. And the Tamil, Malayalam, Bengali, Odia and Assamese calendars name their months by the Sun alone, ingress to ingress, so the month a birth there is recorded under is a solar one, while the tithi is worked out the same way.

The Same Two Degrees Give the Other Limbs

The karana is half a tithi, the elongation in steps of six degrees rather than twelve; its names repeat in a cycle explained under the 11 karanas. The yoga adds the two longitudes instead of subtracting them and counts in steps of 13°20′. Unlike the tithi, the yoga does depend on the zodiac used, because a sum does not cancel the ayanamsa; it must be taken from sidereal positions, and tropical ones put it about four yogas out. The nakshatra uses the Moon alone, its sidereal longitude in the same 13°20′ steps, and the free kundli already prints it. Why the sidereal figures differ from the tropical ones by about 24° is the subject of what the Lahiri ayanamsa shifts.

From Birth Tithi to Hindu Birthday

Once you have the month, paksha and tithi, then by the usual reckoning the Hindu birthday in a given year is the day that tithi holds sunrise in that month. The tithi birthday table gives that day for each lunar month from Kartika 2026 through Margashirsha 2027, and the sunrise days of each tithi through 2026 and 2027 have their own lists under the tithi index. The panchang gives the calendar and this page gives the arithmetic; neither says anything about the person born in a given tithi. In Hindi: जन्म की तिथि कैसे निकालें: जन्म-तारीख से हिंदू तिथि.

In Brief

• Tithi number: (Moon − Sun, plus 360 if negative) ÷ 12, fraction dropped, plus one
• Paksha: 1 to 15 Shukla (15 is Purnima), 16 to 30 Krishna (30 is Amavasya)
• Degrees: printed in full by the free kundli; tropical or sidereal gives the same tithi
• Panchang date: a different tithi for 31% of the minutes of 2027, mostly for births later in the day
• Amanta month: the Sun’s sidereal sign after taking off one-twelfth of the elongation; within 2.5° of a sign edge, check an almanac
• Purnimanta month: one name ahead for a Krishna paksha birth, the same for a Shukla one