Moon Phase Calculator

By the Age-Finder team · Last updated 7 November 2026

The Moon Phase Calculator shows the phase of the Moon on any date: its name, how much of it is lit, how many days into its cycle it is, and the dates of the next full moon and new moon.

How to Use the Moon Phase Calculator

Leave the date empty for today, or choose a day and month and type the year. Select Calculate.

The result shows the phase with a picture of the Moon, the share of the disc that is lit, the Moon’s age in days, and the next full moon and new moon. To find the weekday of a date as well, use the Day of the Week Calculator.

Tonight’s Moon

On Saturday, 7 November 2026, the Moon is a waning crescent, 27.8 days into its cycle. The tool shows 4% lit at midday; the live phase pages show 3%, because the illumination falls by about 3 points a night near new moon and the exact figure depends on the hour sampled.

The previous new moon was on 10 October 2026 and the full moon was on 26 October 2026. The next new moon is on Monday, 9 November 2026, and the next full moon, the Beaver Moon, is on Tuesday, 24 November 2026.

The Eight Phases of the Moon

“Waxing” means the lit part is growing and “waning” means it is shrinking. The Moon’s age counts the days since the last new moon.

How the Calculator Works

The calculator uses the method published by the astronomer Jean Meeus in Astronomical Algorithms, a standard reference for astronomical calculation. It finds the exact moment of each new moon and full moon, then works out where your date falls between them.

We checked it against an independent astronomy library across 1,361 new and full moons from 1950 to 2060, and every time agreed within two minutes.

For a calendar date, the calculator looks at the Moon at midday in your own time zone. Dates of the next full and new moon are shown in your local time zone too, so near midnight the date can differ from listings for another country.

The Formula, If You Want to Work It by Hand

The tool uses the full Meeus method, with a series of periodic terms for the Sun, the Moon and the nodes.

A simpler approximation counts days from a known new moon: take the new moon of 6 January 2000 at 18:14 UTC, count the days to your date, and take the remainder after dividing by 29.530588.

That remainder is the Moon’s age in days. The share lit is (1 − cos(2π × age ÷ 29.530588)) ÷ 2.

The approximation is close but not exact: it put 7 November 2026 at 27.1 days old and 6.5% lit, while the tool’s Meeus method gives 27.8 days and 3.9%. Use the approximation for a rough check, and the tool for the exact figure.

Why the Lunar Cycle Is 29.5 Days

From one new moon to the next takes about 29.53 days on average. This is the synodic month, the time the Moon needs to return to the same position relative to the Sun as seen from Earth. Because the Moon’s orbit is an ellipse, individual cycles vary by several hours either side of the average.

A calendar year is about 11 days longer than 12 lunar cycles, so most years have 12 full moons and some have 13. Between 2020 and 2039, the years with 13 full moons are 2020, 2023, 2026, 2028, 2031, 2034, 2037 and 2039.

When a calendar month has two full moons, the second is often called a blue moon. The synodic month of 29.53 days is not the same as the sidereal month of 27.3 days, which is one complete orbit relative to the fixed stars.

Full Moons of 2026 and 2027

2026 has 13 full moons, 2027 has 12. The names are the traditional monthly names used in North America:

A supermoon has no official definition. The pages cited here call a full moon a supermoon when it falls close to perigee, the point of the Moon’s orbit nearest Earth, using a distance threshold of about 360,000 to 361,885 kilometres.

The Cold Moon of 24 December 2026 is the closest full moon of the year, at about 356,700 kilometres. The other eclipses of 2027 are a total solar eclipse on 2 August, an annular solar eclipse on 6 February, and a penumbral lunar eclipse on 18 July.

Calendars That Follow the Moon

Moon phases still set dates in several calendars: The Islamic calendar is purely lunar: each month begins with the first sighting of the new crescent Moon, so the months move through the seasons. Lunar New Year, used in China, Korea and Vietnam, falls on a new moon between 21 January and 20 February.

Easter is calculated from the first full moon on or after 21 March, using a table of ecclesiastical full moons rather than the observed Moon. Because these rules depend on the Moon, the dates move from year to year in the Gregorian calendar.

For the Chinese zodiac year, which changes at Lunar New Year, use the Chinese Zodiac Finder. For the Easter date, use the Easter Date Calculator. For the Islamic date, use the Hijri Date Converter.

The Moon on Your Birthday

Enter your date of birth to see the Moon on the night you were born. Someone born on 14 May 1990 was born under a waning gibbous Moon, about 77% lit and 19.3 days old, five days past the full moon of 9 May 1990.

The next new moon after that birthday was on 24 May 1990. On the night of the Apollo 11 Moon landing, 20 July 1969, the Moon was a waxing crescent, about six days old and a little over a third lit, which is why the astronauts landed in early morning sunlight on the Moon’s surface.

Northern and Southern Hemispheres

The phase and the percentage lit are the same everywhere on Earth on a given night.

What changes is the view: from the Southern Hemisphere the Moon appears upside down compared with the Northern Hemisphere, so a waxing crescent is lit on the left instead of the right. The picture in the result shows the Northern Hemisphere view.

What the Tool Does Not Show

The tool shows the phase, the share lit, the Moon’s age and the next full and new moon.

It does not show moonrise and moonset times, which need your location; the Moon’s distance from Earth; the zodiac sign or constellation the Moon is in; libration, the slight wobble that lets us see a little around the Moon’s edges; a month calendar of every night; or eclipse dates.

The comparison table below marks which of those the other calculators add.

What other moon phase calculators offer

Most moon phase calculators on the first page give the same phase and illumination this one does. What sets them apart is how much else they show for the same date. The comparison below is against the three moon phase calculators that rank highest.

What this page still lacks: the tool shows no moonrise or moonset, no distance, no zodiac sign, no libration, no month calendar and no eclipse dates.

What it adds is the full Meeus calculation, checked to within two minutes over 1,361 moons from 1950 to 2060, with the phase drawn at its true shape rather than picked from eight pictures.

Frequently Asked Questions

Sources

• The U.S. Naval Observatory phases of the Moon page gives the official dates and times of new and full moons.
• NASA Science explains how the lunar phases work.
• Age-Finder methodology (how dates and moon phases are calculated).