Date & Time Tools
Moon Phase Calculator
Calculate the current or any date's moon phase.
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What is Moon Phase?
A moon phase calculator based on the synodic month. Pick a date and see the phase name, illumination, and days into the cycle.
How it works
The phase is derived from the date's position in the 29.53-day synodic cycle, referenced to a known new moon epoch.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Paste or type any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting exact lunar calendars
The calculation is astronomically close but simplified; official religious and cultural calendars may differ by a day.