Moon Phase Calculator
Pick any date and see the Moon's phase, how much of it was lit, and its age in days. It works for any day — past or future — because moon phases follow precise, predictable orbital math.
- Illumination
- 31%
- Moon age
- 5.6 days
What you get
For your chosen date the calculator returns the named phase (for example Waxing Gibbous), the illuminated percentage of the disk, and the moon's age — the days since the previous New Moon. Together these pin down exactly what the Moon looked like that night. Curious how the number is worked out? See how the moon phase is calculated.
Frequently Asked
How do I find the moon phase for a specific date?
Type or pick the date in the calculator above. It instantly returns the named phase (e.g. Waxing Gibbous), the illuminated percentage of the disk, and the moon's age in days — no sign-up needed.
Can I check the moon phase on my birthday?
Yes. Enter your birth date to see exactly which phase the Moon was in the day you were born and how much of it was lit. For a keepsake version with a reading, try the Birthday Moon page.
Does the calculator work for future dates?
Yes. Moon phases follow precise orbital math, so the calculator is just as accurate for future dates as for past ones — useful for planning weddings, trips, photography or stargazing.
What does moon age mean?
Moon age is the number of days since the last New Moon. 0 days is New Moon, about 14.8 days is Full Moon, and 29.5 days completes one cycle.