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Moon Phase Calculator
Choose a date to estimate the Moon’s phase and illumination, then see the approximate new moon, quarter and full moon moments for that UTC month.
How do I check the Moon phase for a date?
Choose a date from 1900 through 2100 and calculate. The page estimates the phase, approximate illuminated percentage and primary phase moments for that calendar month.
Frequently asked questions
How do I check the Moon phase for a date?
Choose a date from 1900 through 2100 and calculate. The page estimates the phase, approximate illuminated percentage and primary phase moments for that calendar month.
Is my date uploaded?
No. The calculation runs in this browser. It does not use your location, call an astronomy service or save your date.
Are the phase times exact?
No. This lightweight tool uses a mean lunar cycle. Actual primary phase times can differ by several hours, so do not use it as an ephemeris or for time-critical observation.
Does the Moon phase depend on my location?
The geocentric phase is broadly the same worldwide at a given instant. Local moonrise, moonset, visibility and the local calendar date depend on location and are not calculated here.
Does this show religious lunar dates?
No. It does not predict crescent visibility or determine the beginning of a religious month. Follow the relevant local authority or calendar.