Moon Phase Calculator

Want to know what phase the moon is in tonight, or exactly what time the moon rises and sets where you are? This free Moon Phase Calculator shows tonight’s phase, how much of the Moon is lit, its age in the lunar cycle, and precise moonrise, moonset and transit times for any location on Earth.

Moonrise and moonset depend heavily on where you stand, so the tool uses your location (or any city you search) and shows every time in that place’s own timezone. A live map marks your spot and points an arrow toward where to look for the Moon when it is above the horizon.

It runs entirely in your browser — there is nothing to install, no account, and your location is never uploaded. Scroll the built-in month calendar to find the next full moon, new moon and quarter phases at a glance.

How to use the moon phase calculator

  1. Allow location access, or type any city or place into the search box, to set your spot.
  2. Read tonight’s phase, percent illuminated and moon age in the main card at the top.
  3. Check the moonrise, transit and moonset times — shown in the location’s local time.
  4. When the Moon is up, follow the arrow on the map and the “look” direction to find it in the sky.
  5. Use the day arrows or tap a date in the month calendar to see any other night’s phase and times.
  6. Spot the next full moon and new moon, ringed in the calendar.

The 8 moon phases explained

The Moon cycles through eight named phases about every 29.5 days as the sunlit portion we see grows and shrinks:

  • New Moon — the Moon is between Earth and the Sun; the near side is dark.
  • Waxing Crescent — a thin sliver of light appears and grows after sunset.
  • First Quarter — half the disc is lit; high in the sky at sunset.
  • Waxing Gibbous — more than half lit and still growing toward full.
  • Full Moon — fully lit; rises around sunset and sets around sunrise.
  • Waning Gibbous — more than half lit but shrinking after full.
  • Last Quarter — half lit again; rises around midnight.
  • Waning Crescent — a shrinking sliver visible before dawn.

What moonrise, moonset and transit mean

Moonrise is when the Moon climbs above the horizon and moonset is when it dips below it. Transit is the moment in between when the Moon reaches its highest point in the sky — the best time to see or photograph it. Unlike the Sun, the Moon does not rise in the morning and set at night on a fixed schedule: a full moon rises near sunset, while a waning crescent rises just before dawn.

On some days at far-northern or far-southern latitudes the Moon may stay above the horizon all day or never rise at all. The calculator states this honestly instead of inventing a time.

Moon age, illumination and the lunar cycle

The synodic month — one full cycle from new moon to new moon — lasts about 29.53 days. Moon age counts the days since the last new moon, and percent illuminated tracks how much of the disc is sunlit: 0% at new, 50% at the quarters and 100% at full. The tool also shows the Moon’s distance from Earth and flags nights near perigee (a larger “supermoon”) or apogee (a smaller “micromoon”).

How the times are calculated

Phases and positions come from the well-established SunCalc astronomy library, run directly in your browser. Moonrise, moonset and transit are found by tracking the Moon’s altitude across your location’s local calendar day, so “tonight” is correct in every timezone. Coordinates are mapped to a timezone offline and times are formatted for that zone. Place search is proxied through OpenStreetMap / Photon; the basemap is © CARTO. Nothing about your location is stored or uploaded.

Frequently asked questions

What moon phase is it tonight?

Open the tool and it shows tonight’s phase for your location automatically — for example New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter or Waning Crescent — along with the exact percentage of the Moon that is lit and whether it is waxing (growing) or waning (shrinking).

What time does the moon rise and set tonight?

The calculator lists tonight’s moonrise, moonset and transit (the Moon’s highest point) in the local time of the place you choose. Because these times depend on where you are, use the locate button or search your town to get times accurate for your exact spot rather than a generic national figure.

Why does moonrise change about 50 minutes each day?

The Moon orbits Earth roughly once every 29.5 days, moving about 12° eastward against the stars each day. Earth has to rotate a little further to “catch up” to it, so on average the Moon rises and sets about 50 minutes later each day. The exact shift varies with your latitude and the time of year, which is why a live calculator beats a rule of thumb.

What do “percent illuminated” and “moon age” mean?

Percent illuminated is how much of the Moon’s disc is sunlit as seen from Earth — 0% at new moon, 50% at the quarters and 100% at full moon. Moon age is the number of days since the last new moon, counting up to about 29.5 before the cycle restarts. Together they tell you exactly where in the lunar cycle tonight falls.

When is the next full moon and new moon?

The month calendar highlights the next full moon and next new moon dates for your location, and you can step forward or back a day at a time, or tap any date, to read its phase and moon times. The first quarter and last quarter days are ringed too.

Does this work outside the United States?

Yes. It works for any location on Earth. Search any city or place worldwide, or use your current location, and all times are shown in that location’s own timezone — not your browser’s — so the figures make sense wherever you are.

Is my location uploaded anywhere?

No. All of the astronomy is calculated directly in your browser, and your coordinates are never stored or sent to us. Place-name search is the only request that leaves your device, and it goes through Mappr’s own privacy-respecting geocoding proxy. If you decline location access we fall back to an approximate position from your network, clearly labelled as approximate.

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