What is Moon Phase Calculator?

Shows the moon phase and illumination percentage for any date, flags supermoons and micromoons, and previews upcoming lunar events. Switch to the month view for a phase-per-day calendar, or look up the moon you were born under — handy for photographers, gardeners, and stargazers.

Calculations use the SunCalc astronomical library: phase angle, illuminated fraction, the eight named phases from new to waning crescent, and the Earth–Moon distance used to flag supermoons and micromoons. Pick any date between roughly 1900 and 2100 to get its phase, see a preview of the next four major milestones, or open the month grid to scan a whole lunar cycle at once. The birth-moon lookup reads the phase for any date you enter and explains what it means.

How to use

1. Today's moon phase and illumination percentage are shown as soon as you open the page.
2. Select any date using the date picker to see the moon phase for that specific day.
3. Check the upcoming phases panel to see when the next full moon, new moon, and quarter phases occur.

When to use

• Planning a night photography session that needs moonlight or, conversely, dark skies.
• Picking a date for a wedding, festival, or outdoor party with full-moon ambience.
• Checking lunar timing for gardening, fishing, or traditional calendar observances.

Result

A landscape photographer planning a night shoot on March 15 opens Moon Phase Calculator, selects the date, and sees it will be a waxing gibbous at 82% illumination — perfect conditions for moonlit scenery with enough ambient light.

FAQ

How accurate is the illumination percentage shown here?

The illumination fraction is accurate to within a fraction of a percent for any date the tool accepts. It comes from SunCalc, which uses the standard low-precision lunar position formulas from Astronomical Algorithms by Jean Meeus.

Why does the phase shown for today differ slightly from another website?

Different sites use different reference times. We compute the phase for noon in your local time zone, while some sites use UTC midnight or your exact current second. Around the precise moment of new or full moon, those can disagree by a label.

What's a waxing gibbous and why should I care?

Waxing gibbous is the phase between first quarter and full moon, with more than half the disc lit and growing. The moon rises in the afternoon and is high in the sky after sunset, so it's a good window for casual moon watching.

Does the tool handle dates far in the past or future?

Yes, you can pick any date the date input accepts, typically 1900 through 2100. Outside that range the formula still works but accumulated error in the simplified formulas becomes noticeable, so we'd suggest a dedicated ephemeris.

Why is the moon's phase the same wherever I am on Earth?

The phase depends only on the relative positions of the sun, moon, and Earth, which are the same for every observer. What changes with location is whether the moon is above your horizon and how high it sits in your sky.

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