Moon Phase Calculator
See the Moon's phase for any date and time: its shape, how much is lit and how old it is. Find the next full moon and new moon in your time zone, how far away the Moon is, and whether it's a supermoon.
The date and time above, and every time on the page, are in this zone.
South of the equator the Moon looks upside down, so the lit side is on the other side.
Decimal degrees: north and east are positive, e.g. Delhi 28.61, 77.21 · London 51.51, −0.13 · Sydney −33.87, 151.21.
Moon phases around your date
| Phase | Last | Next |
|---|
Moon calendar
Each moon shows the phase at midday in your time zone. Days with a main phase show its time. Your date is outlined.
Islamic (Hijri) months begin with the first sighting of the thin crescent after the new moon, usually one or two evenings after the new moon time shown here. See the month starts in the Hijri date converter.
Full moons
| Full moon | Traditional name | Notes |
|---|
Traditional names come from old North American and European almanacs; other cultures use other names. Supermoon and micromoon use the "within 90% of perigee" rule; definitions vary.
How your moon phase is worked out
Your date, step by step: count the moon cycles since 2000, find the last new moon, then see how much is lit.
- 1
Days since 2000
19 Oct 20:48 UT
− 6 Jan 2000 14:20
= 9,783.27 days - 2
Count moon cycles
9,783.27 ÷ 29.5306
= 331.293
→ cycle 331 - 3
Fix for the orbit
mean 11 Oct 05:21
−13h 29m − ΔT
= 10 Oct 15:50 UT - 4
Age and light
age 9.21 days
61.5% lit
Waxing gibbous
Read more: the formula, a worked example and full moon names
The Moon goes round the Earth once a month, and the Sun always lights the half that faces it. What we call the phase is how much of that lit half we can see. At new moon the Moon is between us and the Sun, so the lit side faces away. At full moon it's on the far side of the Earth, so we see all of the lit side. One whole cycle, new moon to new moon, takes 29.53 days on average, but any single cycle can be up to about 7 hours shorter or 7 hours longer, because the Moon's orbit is an oval and the Sun pulls on it.
The formula
cycles since 2000 = (your date − 6 Jan 2000 14:20) ÷ 29.530589 days, rounded down = k
mean new moon = 6 Jan 2000 14:20 + 29.530589 × k days
true new moon = mean new moon + orbit fixes (25 sine terms in the Moon's and Sun's positions, up to about ±14 hours) − ΔT
age = your date − true new moon
lit share = (1 + cos phase angle) ÷ 2, where the phase angle is the Sun–Moon–Earth angle (180° at new moon, 0° at full moon)
Worked example
Take 13 October 2026 at 12:00 UTC, which is Julian day 2,461,327.0. The mean new moon of 6 January 2000 is Julian day 2,451,550.09766. The gap is 2,461,327.0 − 2,451,550.09766 = 9,776.90 days. Dividing by 29.530589 gives 331.077, so 331 whole cycles have passed: k = 331. The mean new moon of cycle 331 is 2,451,550.09766 + 29.530589 × 331 = 2,451,550.09766 + 9,774.62491 = 2,461,324.72257 (plus 0.00001 for a tiny slow-down term), which is 11 October 2026 at 05:21 (05:20:31). The orbit fixes add up to −0.56203 days, or −13 hours 29 minutes, giving 10 October 2026 at 15:51 in dynamical time. Taking off ΔT (about 76 seconds) gives the new moon at 15:50 UTC on 10 October 2026. The Moon's age is 2,461,327.0 − 2,461,324.15968 = 2.84 days (2 days 20 hours). At that moment the Moon is 33.2° east of the Sun and the phase angle is 146.4°, so the lit share is (1 + cos 146.4°) ÷ 2 = (1 − 0.8328) ÷ 2 = 0.0836, or 8.4% lit: a waxing crescent, 398,217 km away.
The eight phases
| Phase | Age (days, about) | Lit | When you see it |
|---|---|---|---|
| New moon | 0 | 0% | Not visible; rises and sets with the Sun |
| Waxing crescent | 1 to 6 | 1 to 49% | Evening, in the west after sunset |
| First quarter | 7.4 | 50% | Afternoon and first half of the night |
| Waxing gibbous | 8 to 14 | 51 to 99% | Late afternoon to after midnight |
| Full moon | 14.8 | 100% | All night: rises at sunset, sets at sunrise |
| Waning gibbous | 16 to 21 | 99 to 51% | Late evening to morning |
| Last quarter | 22.1 | 50% | Second half of the night and morning |
| Waning crescent | 23 to 29 | 49 to 1% | Before sunrise, in the east |
The calculator calls it a main phase (new, first quarter, full, last quarter) when the exact moment is within 12 hours of your time; otherwise it names the in-between phase.
Supermoons and micromoons
The Moon's distance swings between about 356,400 km at its closest (perigee) and 406,700 km at its farthest (apogee). A full moon near perigee looks about 14% wider and 30% brighter than one near apogee. Here a full moon is a supermoon when its distance is within the closest 10% of the range between the perigee and apogee of that orbit (the "within 90% of perigee" rule of astrologer Richard Nolle, who coined the word), and a micromoon when it's in the farthest 10%. Other sources use a fixed limit such as under 360,000 km, or only count the closest full moon of the year, so their lists can differ. In 2026 the full moons of 24 November (360,765 km) and 24 December (356,738 km) are supermoons, and 31 May (406,135 km) is a micromoon.
Traditional full moon names
These names come mostly from old North American and European almanacs. They are folk names, not official ones, and other cultures and the southern hemisphere use different ones. The Harvest Moon is the full moon nearest the September equinox (so it is sometimes in October), and the Hunter's Moon is the one after it. A Blue Moon is the second full moon in a calendar month.
| Month | Common name | Other name |
|---|---|---|
| January | Wolf Moon | Ice Moon |
| February | Snow Moon | Hunger Moon |
| March | Worm Moon | Sap Moon |
| April | Pink Moon | Egg Moon |
| May | Flower Moon | Milk Moon |
| June | Strawberry Moon | Rose Moon |
| July | Buck Moon | Thunder Moon |
| August | Sturgeon Moon | Grain Moon |
| September | Corn Moon | Barley Moon |
| October | Hunter's Moon | Travel Moon |
| November | Beaver Moon | Frost Moon |
| December | Cold Moon | Long Night Moon |
The Moon and the Islamic calendar
Each Hijri month starts with the first sighting of the thin crescent after the new moon, usually one or two evenings after the new moon time. That is why Ramadan and Eid can start on different days in different countries. The Hijri date converter shows the calculated month starts, with a day shift for local moon sighting.
Method: Jean Meeus, "Astronomical Algorithms", 2nd edition (1998): chapter 49 for phase times, the main terms of chapter 47 for the Moon's position and distance, chapter 25 for the Sun, chapter 48 for the lit share and chapter 15 for rising and setting. ΔT from the Espenak and Meeus formulas. Checked on 13 October 2026 against Meeus's worked examples and an independent ephemeris (PyEphem): phase times within 1 minute, distances within 50 km, moonrise and moonset within a minute. Rise and set times are for sea level with a clear, flat horizon.
Common questions
What is the moon phase today?
The calculator opens on the current date and time in your time zone and shows the phase name, how much of the Moon is lit, its age in days since the last new moon and a drawing of its shape. Change the date or time to see any other moment from 1900 to 2100.
When is the next full moon?
The next full moons of 2026 are on 26 October at 04:12 UTC, 24 November at 14:53 UTC and 24 December at 01:28 UTC. The calculator shows them in your own time zone, along with the next new moon and quarters.
What is a supermoon?
A supermoon is a full moon that happens when the Moon is near the closest point of its orbit (perigee), so it looks slightly bigger and brighter. This calculator uses the common "within 90% of perigee" rule: the distance is in the closest 10% of that orbit's range. Other sources use a fixed limit such as 360,000 km, so lists can differ. The full moons of 24 November and 24 December 2026 are supermoons.
What is a Blue Moon?
In everyday use a Blue Moon is the second full moon in one calendar month. It happens about every two and a half years. 31 May 2026 is a Blue Moon in most time zones, as there is also a full moon on 1 May.
Why does the Moon look different in the southern hemisphere?
People south of the equator see the Moon upside down compared with people in the north. A waxing moon is lit on the right in the north and on the left in the south. Near the equator the lit side points up or down. Choose Southern in Advanced to flip the drawing.
How accurate are these moon phase times?
Phase times use Jean Meeus's method from "Astronomical Algorithms" and are usually within a minute of published tables for 1900 to 2100. Distances are within about 50 km and moonrise and moonset within a minute or two at sea level.
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