How to check the moon phase
- The page opens on tonight's moon. Pick any date to see its phase, or step day by day.
- Read the phase name, how much of the moon is lit and its age in days since the new moon.
- See the dates and times of the next new moon, first quarter, full moon (with its traditional name) and last quarter, and a monthly moon calendar.
Why the moon has phases
The moon does not make its own light; we see the half lit by the sun. As it orbits Earth every 29.53 days (a synodic month), we see that lit half from changing angles. At new moon it sits roughly between Earth and the sun and its dark side faces us; at full moon it is on the far side of Earth and fully lit. In between come the crescent, quarter and gibbous phases, waxing (growing) towards full and waning (shrinking) afterwards. "First quarter" means a quarter of the way through the cycle, when half the disc is lit.
The calculation starts from a known new moon and the mean lunar month, with corrections for the main irregularities of the moon's and Earth's orbits, so event times are usually accurate to within one or two hours. That is plenty for planning night photography, stargazing (darker skies near new moon), fishing, gardening traditions or a full-moon walk; for astronomical precision, consult an almanac. Traditional full moon names such as Harvest Moon and Wolf Moon come from North American and European folklore. Everything is calculated in your browser.
When is the next full moon?
It is listed in the table on the right, with the date and approximate time in your time zone.
How long is a lunar cycle?
About 29.53 days from one new moon to the next.
Is the moon phase the same everywhere?
Yes, but the lit side appears flipped in the southern hemisphere, and the date can differ by time zone.