Moon Phase Calculator

About this tool

Look up and wonder what you are seeing? The Moon Phase tool shows today’s phase and its illumination percentage, so you know whether it is a thin crescent, a half moon or a bright full moon. Gardeners, stargazers, anglers and photographers all care about moonlight, and a quick check helps you decide when to observe faint stars or when to expect a brilliantly lit landscape. The tool works from the average 29.53-day lunar cycle and is accurate to within about a day, which is plenty for everyday planning. You can change the date to see how the phase will look on a particular evening, such as a camping weekend or a holiday. A full moon rises around sunset, so combine this with the Sunset Time page to see when it will appear, and use the Sunrise Time tool to find when it will set in the morning light. For one page that covers daylight, twilight and the moon together, visit Sun & Sky Times. Planning a night-time activity with a group? A Countdown Timer can mark the start of the show, and the Sun & Sky category holds more astronomy helpers.