Calculate the moon phase for any date: new moon, full moon, quarters and crescents, with age, illumination and next moon events. Free online calculator. All processing runs locally in your browser. Your data is not uploaded to any server.
100% Local Processing
How to Use
Enter any date and get the moon phase with its age, illuminated fraction and the approximate dates of the next new and full moons.
Steps
Pick a date. Leave it empty to use today.
Click Calculate.
Read the phase, the moons age, illumination and the next moon events.
What the result shows
The phase name: new, crescent, quarter, gibbous or full.
The age of the moon in days inside the 29.53-day cycle.
Percentage of the disc illuminated.
Approximate dates of the next new moon and next full moon.
Features
Based on the standard synodic month from astronomically anchored epochs.
Phases are labelled exactly, not just by percentage.
Everything is computed in your browser.
All processing runs locally in your browser. Your data is not uploaded to any server.