What was the moon phase on a date?

The moon runs through its phases every 29.53 days. Enter a date to see which phase it was in, roughly how much of the disc was lit, and how far into the cycle it had travelled.

Pick a date

Works for any date — the night you were born, a wedding, a camping trip.

Moon phase

On October 23, 2026 the moon was a 🌔 Waxing Gibbous, about 92% lit.

Phase
🌔 Waxing Gibbous
Illumination
92% of the disc lit
Moon age
12.1 days since the new moon
Waxing or waning
Waxing — growing towards full
Cycle length
29.53 days from one new moon to the next

How it is calculated

  • The calculation counts days from a known new moon on 6 January 2000 and divides by the mean synodic month of 29.530589 days.
  • The remainder is the moon’s age in days; zero is new, about 14.8 is full.
  • Illumination is worked out from the age using a cosine curve, which is a close approximation of the lit fraction seen from Earth.
  • Phase names cover the principal phases within about a day either side, and the crescent and gibbous names fill the gaps.

Where this is used in the real world

  • Sentimental questions — the moon on a birth night, a wedding or an anniversary.
  • Photography and stargazing, where a dark sky near new moon matters.
  • Fishing, gardening and folklore calendars that follow lunar phases.
  • Historical research: night-time events are easier to picture when you know how much moonlight there was.

Good to know

  • This uses the mean lunar month, so the answer can be up to a day out. The moon’s real orbit speeds up and slows down.
  • Phases are the same worldwide at a given instant, but the local date differs by time zone, so a phase that lands near midnight may be listed on the adjacent day where you live.
  • Illumination is the fraction of the disc lit, not how bright the moon looks, which also depends on how high it sits and how clear the sky is.

Questions people ask

What moon phase was I born under?

Enter your birth date. The result names the phase and gives the percentage of the disc that was lit that night.

How accurate is it?

Within about a day. It uses the average length of the lunar month rather than a full orbital model, which is enough for phase names and a close illumination figure.

When is the next full moon?

Step the date forward a few days at a time and watch the phase name change. A full moon comes roughly every 29 or 30 days.