Everyday Tools
Moon Phase Calculator
Today’s (or any date’s) moon phase, illumination and next full moon.
✓ Free
✓ No account
◉ Runs on this device
Everyday Tools
Powering up the tool…
TOOL MOON-PHASE-T
What this tool does
About the moon phase calculator
Real synodic arithmetic — accurate to hours, honest about ephemeris work.
How to use it
- Leave blank for today or pick a date.
- Read phase, age and illumination.
- Note days to the next full moon.
- The phase emoji is copyable — the whole set is on Moon Emoji.
Useful for
- Plan photography around the full moon.
- Check tonight’s sky before heading out.
- Garden by the moon (the maths, at least, is real).
Straight answers
Moon Phase Calculator FAQ
How is the phase computed without an API?
The mean synodic month (29.530588 days) counted from a reference new moon — pure arithmetic, accurate to a few hours. Minute-precise rise times and eclipses need real ephemerides; phase-of-the-night does not.
Does the full moon actually affect sleep/behaviour?
Research is genuinely mixed — small sleep effects appear in some studies, werewolf effects in none. The calculator supplies the moon; the folklore is bring-your-own.