Tithi
A lunar day: a measure of the changing angle between the Sun and Moon. It is not always the same length as a civil day.
A living way of noticing time
Time, written in moonlight.
The Hindu calendar is not one single system. It is a family of regional calendars that attends to the Moon, the Sun, the seasons, and the place from which the sky is observed.
Its purpose is not just counting dates. It gives language to rhythm: waxing and waning, arrival and departure, memory and renewal.
Four words to know
Read the shape of a month
These concepts are shared widely, though their detailed calculation and use can vary by tradition and region.
Pakṣa
One half of a lunar month, made of fifteen tithis. Pakṣa literally evokes a wing or side.
Māsa
A lunar month, containing the bright and dark fortnights. Its name is connected to the full moon’s nearby star group.
Pañcāṅga
An almanac whose name means “five limbs”: tithi, weekday, nakṣatra, yoga, and karaṇa.
Two movements, one whole
A lunar month moves through a bright fortnight and a dark fortnight. They are not opposites to be judged; together, they describe a complete rhythm.
Waxing moon
From new moon toward full moon. The tithis are counted from Pratipadā to Pūrṇimā.
→
Full moon
A moment of fullness — the completing point of the bright fortnight.
→
Waning moon
From full moon toward new moon, ending at Amāvāsyā — a night of little or no visible moon.
One sky, more than one convention
Why month names can differ
Regional calendars often agree on the astronomical tithi while placing it within differently bounded months.
Amānta
The lunar month ends with the new moon (Amāvāsyā). The next day begins a new month with its bright fortnight.
Pūrṇimānta
The lunar month ends with the full moon (Pūrṇimā). The same night in the dark fortnight can therefore carry a different month name.
The important part: this is regional diversity, not a disagreement about the sky. A good calendar always names its location and tradition.
Why the calendar is lunisolar
Twelve lunar months are a little shorter than a solar year. To keep lunar months in step with the seasons, an extra lunar month — adhika māsa — is added when needed. This elegant adjustment lets the calendar listen to both the Moon’s visible cycle and the Sun’s seasonal movement.
Chaitraspring beginning
Vaiśākhagrowing warmth
Jyeṣṭhaearly summer
Āṣāḍhamonsoon approach
Śrāvaṇamonsoon
Bhādrapadalate monsoon
Āśvinaautumn
Kārtikaclear autumn
Mārgaśīrṣaearly winter
Pauṣawinter
Māghalate winter
Phālgunaspring’s return
A gentle caution
Not a universal date converter
This page introduces ideas, not a schedule for observances. Exact dates may vary with locality, sunrise rules, calculation tradition, and whether a community follows a lunar or solar regional calendar. For a family or community date, use a trusted local pañcāṅga.