Moon Phase Calculator
Find the moon phase, illumination percentage, and age for any date.
What is a moon phase calculator?
A moon phase calculator shows the current phase of the Moon and predicts future phases. The Moon completes a full cycle of phases approximately every 29.53 days (a synodic month), moving through new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, and waning crescent.
Understanding moon phases has practical applications: photographers plan shoots around golden hour and moonrise timing, gardeners follow lunar planting calendars, fishermen know that fish feed more actively during new and full moons, and astronomers plan observations based on moonlight interference. Tides are also directly affected by lunar position.
The eight moon phases
- New Moon — the Moon is between Earth and the Sun, invisible from Earth. Best time for stargazing.
- Waxing Crescent — a thin sliver of light appears on the right side (in the Northern Hemisphere).
- First Quarter — exactly half the Moon is illuminated. The Moon is 90 degrees from the Sun.
- Waxing Gibbous — more than half illuminated, approaching full moon.
- Full Moon — the entire visible face is illuminated. The Moon is opposite the Sun from Earth.
- Waning Gibbous — illumination begins decreasing after the full moon.
- Last Quarter — half illuminated on the left side, 90 degrees behind the Sun.
- Waning Crescent — a thin sliver remains before the next new moon.
How to use this tool
The tool displays the current moon phase with a visual representation, illumination percentage, and the Moon's age in the current cycle. You can navigate forward and backward in time to see past and future phases. Key dates for upcoming full moons and new moons are highlighted.
Frequently asked questions
Why does the Moon appear to change shape?
The Moon does not actually change shape. As it orbits Earth, we see different portions of its sunlit half. When the Moon is between Earth and the Sun, we see its dark side (new moon). When Earth is between the Moon and the Sun, we see its fully lit side (full moon). The phases are simply different viewing angles of the same half-lit sphere.
Is the moon phase the same everywhere on Earth?
Yes, the moon phase is the same globally at any given moment — a full moon is a full moon everywhere. However, the Moon's orientation appears flipped between the Northern and Southern Hemispheres, and the Moon rises and sets at different times depending on your location. The phase itself (percentage illuminated) is identical worldwide.