About moon phase calculator
The moon cycles through phases about every 29.5 days. The calculator shows the phase, how much of the disc is lit and the dates of the next full and new moon.
The phases
- New moon, waxing crescent, first quarter, waxing gibbous.
- Full moon, waning gibbous, last quarter, waning crescent.
Cultural dates
Many Indian festivals and fasts follow the lunar calendar, with Purnima at the full moon and Amavasya at the new moon. For religious dates, follow your local panchang, which accounts for regional rules.
A worked example
A lunar cycle lasts about 29.5 days. If a full moon falls on 1 January, the next one is around 30 or 31 January, and the new moon in between is about 15 January. The moon is half lit at the first and last quarters.
Skywatching tips
Stargazing is best around the new moon, when the sky is darkest. The full moon rises near sunset and sets near sunrise, so it is up all night.
