Moon phase calculator
Choose a date to see what the Moon looks like. The calculation uses the average length of a lunar cycle, so it can be off by up to a day.
| Phase | – |
| Age of the Moon | – |
| Illuminated | – |
| Next full moon | – |
| Next new moon | – |
Why does the Moon have phases?
The Moon does not shine by itself; it reflects sunlight. One half of it is always lit by the Sun, but as the Moon orbits the Earth we see that lit half from a changing angle. At new moon the lit side faces away from us, at full moon it faces us completely, and in between we see a crescent, a half or a gibbous Moon.
A full cycle from one new moon to the next takes about 29.5 days. That is why a calendar month is roughly as long as one cycle of phases.