Moon Phase
Tonight's moon phase, any date's, and the next full and new moons.
About this tool
Tonight's moon, its illumination percentage and its age in the 29.53-day cycle, plus the dates of the next full and new moons โ and a date picker for any date past or future (what was the moon on the night you were born?). Computed from the moon's synodic period, accurate to within a few hours; the same phase is visible worldwide on the same night.
Reading the cycle
The eight named phases are waypoints on one continuous loop: new (invisible, moon between us and the sun), waxing crescent through first quarter (right half lit, for northern observers) and waxing gibbous to full โ then the waning mirror back to new. Two practically useful facts: the full moon rises at sunset and sets at sunrise, so it's up all night โ glorious for walks, terrible for stargazing, since its glare washes out faint objects (planets don't care); and the quarter moons, counter-intuitively, are the best nights for looking at the moon itself through binoculars โ shadows along the terminator give the craters their depth. Pin the next full moon with a countdown if you're planning around it.
Frequently asked questions
How accurate is the phase calculation?
Within a few hours โ it uses the mean synodic month (29.53 days) anchored to a known new moon. For calendar questions (which night is full?) that's exact enough; astronomical almanacs add per-orbit corrections.
Is the moon phase the same everywhere on Earth?
Yes โ everyone sees the same phase on the same night. What changes with location is the moon's orientation in the sky and its rise time, not how much of it is lit.
Why is a full moon bad for stargazing?
It's up all night (rising at sunset) and bright enough to wash faint stars, nebulae and the Milky Way out of the sky. Planets and the moon itself remain fine targets.
When's the best phase to look at the moon through binoculars?
Around the quarters โ sunlight strikes the surface at a low angle along the day/night line, throwing crater shadows that make the terrain leap out. A full moon is lit flat and looks strangely two-dimensional.