What is Tithi?
तिथि
A tithi is a lunar day in the Hindu calendar — the time it takes the Moon to gain 12° on the Sun. Nepali festivals and rituals are fixed to tithis (e.g. Purnima/full moon, Amavasya/new moon, Ekadashi), which is why their Gregorian dates shift each year.
There are 30 tithis in a lunar month, split into the waxing (Shukla Paksha) and waning (Krishna Paksha) fortnights.
Because tithis don't align with solar days, festivals like Dashain and Tihar move within a range of weeks each Gregorian year.
Sources & data note
Definitions explain standard Nepali terms in everyday and official use. Land-unit conversions follow the standard Nepali measurement system; tax and contribution rates reflect current law (Income Tax Act 2058, VAT Act 2052, Social Security Act 2074) and are revised each fiscal year by the Finance Act — always confirm current-year figures with the relevant authority.