Eight named phases
The 29.53 day cycle is split into eight phases: New, Waxing Crescent, First Quarter, Waxing Gibbous, Full, Waning Gibbous, Last Quarter and Waning Crescent.
Moon Phase Viewer
See what the moon looked like on any date, or what it will look like. Get the phase name, illumination percentage, moon age, and the next full moon and new moon dates.
New Moon
0% illuminated
Pick a date
Choose any date to see that day's moon phase. Use Today to jump back to now, or step one day at a time.
0.0Moon age (days)
—Next full moon
—Next new moon
ⓘUses a standard astronomical approximation (a synodic month of about 29.53 days), so results can be off by roughly up to a day depending on your timezone. It does not require your location.
How the moon phase is calculated
Synodic month math
Moon age is measured from a known reference new moon, then wrapped into the current 29.530588853 day synodic cycle to find today's position.
Good, not perfect
This is a well known astronomical approximation, not a live ephemeris. It is normally accurate to well within a day.
FAQ
Do I need to enter my location?
No. Moon phase depends only on the date, not your location, so this tool works the same anywhere in the world without needing GPS or an address.
How accurate is the moon phase shown?
It uses a standard astronomical approximation based on the synodic month, about 29.53 days. Results can be off by roughly up to a day depending on your timezone and the exact time of day.
How is the illumination percentage calculated?
Illumination is estimated from the moon's age within its 29.53 day cycle using a cosine based formula, the same general approach used by many calendar and planetarium apps.