Moon Phase Calculator — Any Date, Phase & Illumination

How to use

1. Pick a date — it defaults to today.
2. Press Get moon phase.
3. Read the phase name, emoji and illumination percentage.
4. Note the next new and full moon dates for planning.

General information only — not medical, financial or legal advice. Figures cross-checked against public official sources (IRS / HMRC / NHS / WHO guidance); content last reviewed September 2026. For decisions that matter, confirm with a licensed professional in your country.

About this tool

The moon repeats itself every 29.53058867 days — the mean synodic month — and that single number powers this page. Counting from the reference new moon of January 6, 2000 (18:14 UTC), the tool converts any date you pick into a moon age, which maps to one of eight phases with its emoji, an illumination percentage and the approximate dates of the next new and full moons. It is deliberately simple sky math rather than a full ephemeris: expect accuracy within roughly a day, which is perfect for planning a stargazing night, a moonlit walk or a lesson plan. The date box defaults to today; past and future dates work the same. No internet connection is needed after the page loads, and nothing about your queries ever leaves your device.

FAQ

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