PK Systems PK Systems
EN PT ES
Date & time

Moon Phase

Get the moon phase, illumination percentage and lunar age for any date, with an accurate moon disc rendered live.

Moon Phase

Moon on this date

—
Illumination
—
Lunar age
—
Distance
—
Next new moon —
Next first quarter —
Next full moon —
Next last quarter —

What is a moon phase?

The moon orbits Earth once every 29.53 days — the synodic month. Because we always see the side lit by the Sun, the apparent shape of the lit fraction shifts continuously through eight named phases: new, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, last quarter, waning crescent. Waxing means the lit fraction is growing toward full; waning means it's shrinking toward new.

How to use it

Pick any date in the picker, or use the quick buttons to jump a day or a week at a time. The moon disc redraws to match the lit fraction, the percentage and lunar age update, and you'll see the dates of the next four major phases (new, first quarter, full, last quarter). All values are computed for noon in your local time zone, which is the convention used by most observatories and almanacs for a single-day phase value.

Reading the moon disc

In the northern hemisphere, the lit edge of a waxing moon appears on the right; for a waning moon, it's on the left. The terminator (the boundary between light and dark) is the most striking feature to observe with binoculars or a telescope — craters near the terminator cast long shadows that reveal mountains and ridges that look flat at full moon. Full moons happen near sunset and stay up all night; new moons rise and set with the Sun and aren't visible at all.

The eight phases at a glance

New (0% lit): moon is between Earth and Sun, invisible. Waxing crescent (1–49%): visible in the western sky after sunset. First quarter (~50% lit, right side): rises around noon, sets around midnight. Waxing gibbous (51–99%): rises in the afternoon, very bright. Full (100%): rises at sunset, opposite the Sun. Waning gibbous: rises after sunset, visible most of the night. Last quarter (~50% lit, left side): rises around midnight, sets around noon. Waning crescent: visible in the eastern sky before sunrise.

Frequently asked questions

How accurate is the phase calculation?
The illumination percentage is accurate to better than 0.5% for any date between roughly 1900 and 2100 — well below what the eye can distinguish. Lunar age is accurate to about a few hours. Phase boundaries (when the moon transitions from one named phase to the next) are accurate to under an hour.
Why does it show illumination at noon instead of right now?
The moon's illumination changes by roughly 3% per day, so a single 'today' value isn't an instant — it's a representative figure for the date. Using local noon gives a stable reference point that observers and almanacs agree on. If you need illumination at a specific minute, pick that day and add a fraction of the per-day change (~0.13% per hour around quarter phases).
What's the difference between new moon and a solar eclipse?
Every solar eclipse happens at new moon, but not every new moon causes an eclipse. The moon's orbit is tilted ~5° relative to Earth's orbit, so most new moons pass slightly above or below the Sun. An eclipse only occurs when the new moon also crosses the ecliptic plane (a 'node'), which lines up roughly twice a year.
Why does the moon look different in the southern hemisphere?
The geometry is the same, but observers below the equator see the moon 'upside down' relative to the northern view. A waxing crescent that appears as a right-side smile in Paris looks like a left-side smile in Sydney. The disc above is drawn from a northern-hemisphere perspective; mentally flip it horizontally if you're observing from the south.
Does this account for the moon's distance and supermoons?
The distance value uses the leading periodic terms in the Moon's orbit (E−M, 2D−M, 2D, 2M), so a 'supermoon' (full moon at perigee, ~356,500 km) and 'micromoon' (full moon at apogee, ~406,700 km) will both show up correctly. Whether a given full moon counts as a 'super' moon is a media term, not an astronomical one — there's no fixed cut-off.
Are the next-phase dates in my time zone?
Yes. The four 'next phase' dates are absolute moments computed in UT and then formatted using your device's time zone. If you're far east or far west of the prime meridian, your local date for the same lunar event may differ from one published in a US or European almanac by a day.
Duration Calculator Race Time Predictor (Riegel formula) JWT Decoder Earth Letters Percentage Calculator Case Converter