Calculating...
Moon phase preview
Schematic 3D-style illustration, not a lunar photograph or an exact sky orientation.
Lunar snapshot
Upcoming principal phases
After your selected date & timeEvent dates are approximate and can fall on a neighboring day. For precise timings, use an official astronomical ephemeris.
Explore the Moon's changing phases
Use this moon phase calculator to explore a selected date, estimate the illuminated part of the lunar disc, and compare phases across a month. The clickable moon phase calendar helps you follow the transition from a new moon through waxing phases to a full moon, then through waning phases toward the next cycle.
What does illumination mean?
Illumination describes the sunlit fraction of the Moon's disc as seen from Earth. It is not a brightness forecast. A quarter moon has roughly half its visible disc illuminated; the word quarter refers to its position in the lunar cycle.
Waxing, waning and lunar age
Waxing describes the part of the cycle approaching full moon; waning describes the part returning toward new moon. Lunar age is the elapsed time since the previous new moon. A complete phase cycle averages about 29.5 days, but individual cycles vary.
Moon phase calculator: common questions
Why does the time zone matter?
A lunar event happens at the same instant worldwide, but its calendar date can differ by time zone. Device local time uses your browser's system time zone; UTC uses Coordinated Universal Time. Switching the time basis preserves the selected instant and updates the input fields.
Does the Moon look different in the Southern Hemisphere?
The phase and illuminated fraction are effectively the same at a given instant, but the apparent orientation changes with the observer's location and the Moon's position in the sky. The hemisphere selector rotates this schematic illustration by 180 degrees; it does not calculate your exact viewing angle.
Can this calculate moonrise, eclipses or religious dates?
No. Moonrise and moonset require location and horizon calculations. Eclipse predictions and religious-calendar decisions need additional methods and authoritative guidance. A new moon estimate does not predict whether a thin crescent will be visible.
Why are phase names approximate?
New moon, the quarters and full moon are specific astronomical events. For a readable label, this tool uses a small interval around each principal phase; intermediate dates are labeled crescent or gibbous. The event cards show the model's estimated principal-phase dates.