Loading...
Find the moon phase for any date. See illumination, moon age, and all 8 phase names.
A moon phase is one of eight distinct appearances of the Moon as observed from Earth, determined by the relative positions of the Moon, Earth, and Sun during the 29.5-day lunar cycle.
Defaults to today. Enter any date from 1900 to 2100.
More than half the Moon is lit, growing toward full.
| Phase | Days | Lit |
|---|---|---|
| New Moon ๐ | 0 | 0% |
| Waxing Crescent ๐ | 1.85 โ 7.38 | 1โ49% |
| First Quarter ๐ | 7.38 โ 9.22 | ~50% |
| Waxing Gibbous ๐ | 9.22 โ 14.77 | 51โ99% |
| Full Moon ๐ | 14.77 โ 16.61 | 100% |
| Waning Gibbous ๐ | 16.61 โ 22.15 | 99โ51% |
| Last Quarter ๐ | 22.15 โ 23.99 | ~50% |
| Waning Crescent ๐ | 23.99 โ 29.53 | 49โ1% |
Formula
Moon Age = (Days since Jan 6, 2000 ref. new moon) mod 29.53059 | Illumination = (1 โ cos(Age รท 29.53059 ร 2ฯ)) รท 2 ร 100%Reference New Moon = January 6, 2000 at 18:14 UTC โ a known new moon used as the epoch
Moon Age = days elapsed since the last new moon (0โ29.53 days)
29.53059 = synodic lunar cycle โ the average time from new moon to new moon
Worked Example
Moon phase on February 19, 2026
Did you know? The lunar cycle (29.53059 days) doesn't divide evenly into a solar year (365.25 days) โ which is why calendar months don't align with moon phases and the same phase can fall on any day of the month from year to year.
Sources
Calculate your exact age in years, months, and days. See days until your next birthday.
Live countdown to your next birthday with zodiac sign and day-of-week info.
Live countdown to any future date with days, hours, minutes, and seconds display.
Find the exact difference between two dates in years, months, days, weeks, and business days.
Find the ordinal day number for any date with days remaining and year progress.
Calculate jet lag recovery time and get direction-specific tips for any international flight.