Moon Phase Calendar
Lunar phase for every day of any month — pure JS, no API.
About Moon Phase Calendar
What this does
An offline moon-phase calendar. The badge at the top shows today's phase name, matching emoji, illumination percentage, and lunar age in days. The month grid shows every day with the correct waxing / full / waning / new emoji plus its illumination.
The method
A simple synodic-cycle calculation from a known new-moon epoch (2000-01-06 18:14 UT) modulo 29.53058867 days. Accurate to about a day, which is fine for a visual calendar — for astronomer-grade timing (rise/set times, exact phase moment) you'd need a proper ephemeris.
Why it's handy
- Photographers planning a night shoot around a full moon
- Farmers, fishermen and gardeners tracking lunar cycles
- Anyone with a curious kid who asks 'what does the moon look like tonight?'
- Fantasy / TTRPG DMs who want in-world moon phases
Frequently asked questions
Within ~1 day for the named phase — good enough for a calendar view. For exact rise / set times, use an astronomy tool.
The lunar age is a global figure — from anywhere on Earth the phase name is the same. What differs is when the moon rises and how high it climbs.
Yes — everything is pure JavaScript. No API calls.
Those need your latitude / longitude and a proper ephemeris — out of scope for this simple calendar.
Embed this tool on your site
Drop a one-line iframe snippet into any blog, lesson plan, or knowledge base. Powered-by-Toolenza link included.
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Paste this snippet into any HTML page. The tool runs entirely in your reader's browser.
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Moon Phase Calendar
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