Moon Phase Calculator

Shows the Moon's phase, illumination percentage and sign for any date, plus the dates of the next New and Full Moon.

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How this calculator works

What it does: Shows the Moon's phase, illumination percentage and sign for any date, plus the dates of the next New and Full Moon.

You enter: Date (optional, default today), Reference date YYYY-MM-DD (optional).

Method: Planetary positions are computed for your date, time and place using the Swiss Ephemeris, then read with standard tropical or sidereal rules.

Result: Press Calculate above to see your full result; the detailed interpretation is explained below.

ⓘ Astrological calculation for educational interest and entertainment. Reflects traditional astrological belief, not scientific proof.

See the Moon's phase for any date at a glance. This calculator shows the current phase, from New to Full and back, how much of the Moon is lit, and which zodiac sign it is passing through, plus the dates of the next New and Full Moon. It is handy for moon-watching, planning and lunar-aware practices.

The Eight Phases

The Moon cycles through eight phases over about twenty-nine and a half days, from the dark New Moon through the Waxing Crescent, First Quarter and Waxing Gibbous to the Full Moon, then waning back through Gibbous, Last Quarter and Crescent. The calculator names the phase for your date and gives the illuminated percentage, so you know exactly how the Moon looks that night.

Waxing and Waning

The half of the cycle from New to Full is waxing, when the lit portion grows, and the half from Full to New is waning, when it shrinks. Many traditions read the waxing Moon as a time for starting and building and the waning Moon as a time for releasing and finishing, which is why people track the phase for timing intentions.

Phase, Sign and Upcoming Moons

Alongside the phase the tool shows the Moon's zodiac sign, which colours the mood of the day, and the dates of the next New and Full Moon, the two points many people plan around. Whether you follow the Moon for gardening, ritual or simple curiosity, it puts the key facts about any date in one place.

Looking Up a Moon Phase

Pick the date you want to check, whether that's a birthday, an anniversary or today, and press Calculate. You'll get the Moon's phase on that date, its illumination percentage and the sign it sat in, plus the dates of the next New and Full Moon. It's a quick way to place any day against the rhythm of the lunar cycle.

Why the Sign Changes So Often

The Moon is the quickest of the visible bodies, crossing a whole zodiac sign in about two and a half days, so the phase and the sign it sits in shift far faster than the Sun's. That's why the tool reads the exact date you enter rather than a whole month at once, and why the same phase can fall in a different sign from one cycle to the next.

Tracking the Next New and Full

Along with the phase for your chosen date, the calculator gives the dates of the upcoming New and Full Moon. People use that to plan around the lunar rhythm, from a simple wish to know when the next full moon falls, to older gardening and folk customs that timed tasks by the waxing and waning light. It's a quick way to line a date up with the cycle. Because the dates are calculated rather than looked up from a table, they stay accurate for any year you choose.

Moon Phase Questions Answered

What are the Moon's phases?

There are eight: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter and Waning Crescent, cycling over about twenty-nine and a half days.

What is the difference between waxing and waning?

Waxing is the half of the cycle from New to Full, when the lit part grows, and waning is from Full back to New, when it shrinks. Traditions link waxing to building and waning to releasing.

When is the next Full Moon?

The calculator shows the dates of the next New and Full Moon for whatever date you enter, computed from the real positions of the Sun and Moon.

Positions are computed with the Swiss Ephemeris. Astrological interpretations are traditional and are offered for reflection, not as guaranteed predictions.

Explore more

Pair this with a few other astrology tools to dig a little deeper: Retrograde Calendar Calculator, Transit Calculator, Synastry Calculator and Composite Chart Calculator. They use different methods to reach the same goal, so a quick comparison is always worthwhile. There is more to discover under astrology calculators, or jump straight to all calculators.

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