Moon Phase Software

Tools & method

Moon Phase Calculator for an exact date and time

Enter a local civil date, 24-hour time, and IANA time zone. The tool converts that instant to UTC and calculates the Moon's geocentric phase angle, illuminated fraction, lunar age, direction, and adjacent principal events.

Calculation input




Use an IANA name so historical daylight-saving rules are applied. The default is UTC.

Calculated Moon state

Schematic Moon phase: waning, 15.82% illuminated at a phase angle of 313.42 degrees. This represents illuminated fraction only, not sky orientation or observer hemisphere.
Schematic illumination only — not sky orientation or observer hemisphere.
Phase
Waning Crescent
Illuminated fraction
15.82%
Lunar age
25.672 days
Direction
waning
Nearest principal event
Last Quarter, previous, 3 days, 23 hours, 16 minutes away
Phase angle
313.4169°
Selected instant in Europe/London
2026-02-13T12:00+00:00[Europe/London]
UTC instant
2026-02-13T12:00:00.000Z
Show every previous and next principal phase
Previous and next event for each principal phase
EventPrevious in Europe/LondonPrevious UTCNext in Europe/LondonNext UTC
New MoonSunday, 18 January 2026 at 19:52:39 GMT2026-01-18T19:52:39.367ZTuesday, 17 February 2026 at 12:01:47 GMT2026-02-17T12:01:47.328Z
First QuarterMonday, 26 January 2026 at 04:47:56 GMT2026-01-26T04:47:56.246ZTuesday, 24 February 2026 at 12:28:08 GMT2026-02-24T12:28:08.778Z
Full MoonSunday, 1 February 2026 at 22:09:49 GMT2026-02-01T22:09:49.657ZTuesday, 3 March 2026 at 11:38:32 GMT2026-03-03T11:38:32.022Z
Last QuarterMonday, 9 February 2026 at 12:43:45 GMT2026-02-09T12:43:45.995ZWednesday, 11 March 2026 at 09:39:07 GMT2026-03-11T09:39:07.989Z

How to read the result

Phase angle is the Moon's geocentric ecliptic longitude relative to the Sun: 0° is new Moon, 90° first quarter, 180° full Moon, and 270° last quarter. Lunar age is the elapsed UTC time since the strictly preceding calculated new Moon; it is not the time since an observed local moonrise.

Principal event times are instants and therefore do not change when the display time zone changes. Only their local representation changes.

Scope and limitations

See the phase calculation methods and astronomical sources. For the same exact instant, calculate Moon distance and apparent size, or add an observer location in the Moon Position Calculator. The Lunar Eclipse Finder searches global events before and after a selected time.