Tithi Meaning: The Lunar Day in Vedic Astrology

A tithi is the lunar day of Vedic astrology: the time the Moon takes to pull 12 degrees further ahead of the Sun. The Moon moves faster than the Sun, so the gap between them keeps widening; each time it opens by another 12 degrees, a new tithi begins. Thirty tithis, 12 degrees each, complete the full 360-degree circle of one lunar month, from new moon to new moon. The tithi is the heart of the panchang, the five-limbed Vedic almanac: festivals and fasts are fixed by it, the quality of a day is read from it, and the lunar calendar counts its dates by it rather than by the civil day.

This page goes deep on the tithi alone. For the other four limbs and how they combine, start with the panchang.

How a tithi is measured

A tithi is a span of angle, not of clock time. It covers exactly 12 degrees of the Moon's gain on the Sun, however long that takes. Because the Moon's speed varies along its orbit, a tithi averages a little under 24 hours but can run from just under 20 hours to nearly 27.

The arithmetic is clean. At the new moon the Sun and Moon stand together, zero degrees apart. By the time the Moon has gained a full 180 degrees, it stands opposite the Sun, fully lit: the full moon. At 360 degrees of gain the two meet again and a new month begins. Twelve degrees, thirty times, is the whole circle, which is why a lunar month of about 29 and a half days holds exactly 30 tithis.

The bright and dark fortnights

The 30 tithis split into two fortnights of fifteen, called pakshas, or wings. Shukla paksha, the bright fortnight, runs from new moon to full as the Moon waxes; krishna paksha, the dark fortnight, runs from full back to new as it wanes. The same fifteen names are used in each, counted Pratipada to Purnima or Amavasya.

The two halves carry opposite readings. The waxing Moon is the time of growth, beginnings, and increase, which is why muhurta work leans toward the bright fortnight for launches and weddings. The waning Moon suits completion and release: finishing, clearing, letting go. Neither half is good or bad; each has its own work.

The 30 tithis and their five groups

The classics sort the tithis into five repeating groups of three, and the group is the fastest way to read a tithi's character. The cycle runs nanda, bhadra, jaya, rikta, purna, and then repeats, so the 1st, 6th, and 11th tithis are all nanda days, the 2nd, 7th, and 12th all bhadra, and so on through both fortnights.

One naming note saves confusion later: bhadra here is a tithi group, a different use of the word from Bhadra the karana, which is the one half-tithi tradition avoids. The two share a name and nothing else.

What the five groups mean

The group names are plain Sanskrit. Nanda means joy: the 1st, 6th, and 11th favour celebration and fresh starts. Bhadra means well-being: the 2nd, 7th, and 12th suit steady, useful work. Jaya means victory: the 3rd, 8th, and 13th back efforts that need to be won. Purna means full: the 5th, 10th, and 15th carry things to completion.

Rikta means empty, and the 4th, 9th, and 14th are the days muhurta work plans around. The framing is practical rather than fearful: a rikta day is not a danger, it is a day whose energy suits clearing, maintenance, and rest rather than a launch. Since a rikta tithi passes within a day and the next favourable tithi is never more than a day or two away, working with the cycle costs almost nothing.

Amavasya and Purnima

Two tithis stand above the rest. Amavasya, the new moon, is the dark meeting of Sun and Moon, the last tithi of the dark fortnight. It is kept as a day of stillness and is sacred to the ancestors, the traditional day for rites of remembrance. Purnima, the full moon, is the bright opposition, a peak of light prized for worship, vows, and sacred acts.

The pair anchors the whole calendar. Southern and western India end the month at amavasya, the north at purnima, which is why the same festival can sit in differently named months in different regions while falling on the very same day.

Tithis, festivals, and fasts

The sacred year runs on tithis, which is why festival dates move against the civil calendar. Diwali's Lakshmi Puja falls on an amavasya; Holi burns on the purnima of Phalguna; Guru Purnima honours teachers on the full moon of Ashadha; Mahashivratri is kept on the 14th of a dark fortnight; Krishna Janmashtami on a dark 8th; Ganesh Chaturthi on a bright 4th.

Ganesh Chaturthi makes a useful point: the 4th is a rikta tithi, yet it is Ganesha's great day. The quality groups guide the choosing of times for new undertakings; festival observance is devotion fixed to a tithi, and the two systems answer different questions. The 11th tithi, ekadashi, shows the same pattern: a fasting day kept twice a month, in both fortnights, by tradition across India.

When a tithi skips or repeats

Matching a lunar day of 20 to 27 hours against fixed sunrises produces two bookkeeping effects. A short tithi that begins after one sunrise and ends before the next never governs a day: the civil count jumps over it, and the almanac calls it a kshaya, or lost, tithi. A long tithi that spans two sunrises governs both days, a vriddhi, or repeated, tithi.

The governing rule itself is simple: the tithi running at sunrise is the day's tithi, the one that names the date and fixes the observances. The almanac prints ending times precisely so that you know which hours of the day belong to which tithi; today's panchang shows the running tithi and when it ends at your location.

The tithi of your birth

The same measurement read at a birth moment gives the janma tithi, the lunar day you were born on. The classical natal texts read the panchanga of the birth itself, the tithi among its limbs, as a colour over the chart: a bright-fortnight birth and a dark-fortnight birth give the Moon a different strength, since a Moon near full is counted bright and strong, and one near new dim.

The janma tithi also fixes personal observances, since birthday rites in the lunar tradition return with the tithi rather than the civil date. To see your own, a free birth chart computes the full panchanga of your birth moment, and the muhurta guide shows how the day's tithi is weighed when choosing a time to begin.