Articles

Tithi: the lunar day

A tithi is a lunar day, the time in which the angle between the Moon and the Sun changes by 12°. A lunar month has 30 tithis. They are the backbone of the Indian calendar: festivals, fasts and the choice of days for action all follow the tithi.

JyotiSoft editorial team · dates checked by calculation

In short

1 tithi = 12° of Moon–Sun separation; 30 in a month.
Shukla paksha is the waxing Moon (tithis 1–15), krishna paksha the waning.
Five groups: nanda, bhadra, jaya, rikta, purna.
Purnima is the full Moon, Amavasya the new Moon, Ekadashi the 11th tithi.
The tithi at sunrise usually counts as the tithi of the day.

№	Name	Favours
1 / 16	Pratipada	beginnings and foundations
2 / 17	Dvitiya	lasting works, building, adornment
3 / 18	Tritiya	arts, music, self-care
4 / 19	Chaturthi	removing obstacles; not for starts
5 / 20	Panchami	healing, medicine, good deeds
6 / 21	Shashthi	health, overcoming obstacles
7 / 22	Saptami	journeys, vehicles, moving
8 / 23	Ashtami	protection, firmness, spiritual practice
9 / 24	Navami	bold, hard tasks; not for starts
10 / 25	Dashami	success, good deeds, travel
11 / 26	Ekadashi	fasting, prayer, spiritual practice
12 / 27	Dvadashi	rituals, charity
13 / 28	Trayodashi	friendship, joy, celebrations
14 / 29	Chaturdashi	harsh tasks; not for starts
15	Purnima	fullness, rituals, good beginnings
30	Amavasya	ancestors, rest, silence; not for starts

How to calculate the tithi: five steps

The longitudes of the Sun and Moon. Take the positions of the Sun and the Moon for the moment you need. The zodiac does not matter: the difference is the same in tropical and sidereal terms.
The difference. Subtract the Sun's longitude from the Moon's. If the result is negative, add 360°. This is how far the Moon has moved ahead of the Sun.
Divide by 12°. Angle ÷ 12°: the whole part plus one is the number of the tithi in the lunar month, from 1 to 30.
The paksha. Tithis 1–15 belong to Shukla paksha (the waxing Moon), 16–30 to Krishna paksha (the waning Moon); in the second half subtract 15. The 15th of Shukla is Purnima, the 30th is Amavasya.
The tithi of the day. In the calendar a day carries the tithi running at sunrise in your city, even if it ends an hour later.

Move the Moon: tithi calculator

The angle is how far the Moon has moved ahead of the Sun. Drag the slider and watch the tithi and the Moon's phase change.

Moon − Sun angle: 43°

How a tithi is counted

The Moon gains on the Sun about 12° a day. When the gap reaches 12° the second tithi begins, at 24° the third, and so on to 360°. Because the Moon's speed varies, a tithi lasts from 19 to 26 hours. Sometimes a whole tithi fits between two sunrises (kshaya tithi) or spans two sunrises (adhika).

A worked example

14 October 2026, 12:00 Istanbul time. The Moon is 43.03° ahead of the Sun. 43.03 ÷ 12 = 3.59: the whole part is 3, plus one — the 4th tithi is running, Chaturthi of Shukla paksha. About 13% of the disc is lit: a thin waxing crescent. The same tithi stands for that day on the Istanbul panchang page.

Two halves of the month

Shukla paksha, the “bright half”, runs from new Moon to full Moon: tithis from Pratipada (1) to Purnima (15). Krishna paksha, the “dark half”, runs from full Moon to new Moon: from Pratipada to Amavasya. The waxing Moon is traditionally the better time for beginnings.

The five groups

The tithis repeat five qualities: nanda (joy — 1, 6, 11), bhadra (welfare — 2, 7, 12), jaya (victory — 3, 8, 13), rikta (empty — 4, 9, 14) and purna (full — 5, 10, 15/30). Rikta tithis are usually avoided for beginnings but suit cleansing and finishing.

Important tithis

Ekadashi (11th) is a fast day devoted to Vishnu, twice a month; see Ekadashi. Purnima is the full Moon, a day of festivals and offerings. Amavasya is the new Moon, a day for remembering ancestors. The chaturdashi of krishna paksha is linked with Shiva (Shivaratri).

Questions

How is a tithi different from a calendar day?

A calendar day runs midnight to midnight; a tithi follows the Moon–Sun angle and can start at any time of day.

What is today's tithi?

The panchang for your city shows it; the JyotiSoft Mini App gives exact start and end times.

What is a kshaya tithi?

A tithi that begins and ends between two sunrises and so “disappears” from the calendar.

Why is a festival sometimes held on two days?

When a tithi spans two sunrises (adhika), traditions choose different days.

What you can do next with your chart

Free

Chart calculator

Lagna, planets by sign and house, nakshatras and dashas — in a minute, no sign-up.

Calculate my chart — free

PDF · pay at once

Complete Natal Chart

Your whole chart in one document of 60–100 pages — to read, reread and share with people close to you.

Character, work, relationships, health, money
A Vedic interpretation of current and coming periods
An audio edition if you like

1499 ⭐

Buy

You pay with Telegram Stars right after the form; the PDF arrives in the chat.