Everyday Utilities
Enter a date to find the current moon phase, illumination percentage, and upcoming lunar events.
Moon Phase
First Quarter49.8% illuminated
First Quarter
Moon phase is calculated from a reference new moon (2000-01-06 18:14 UTC) using the synodic month of 29.53 days.
A moon phase calculator is a digital tool that determines the lunar phase (new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, or waning crescent) for any given date. It calculates the moon's illumination percentage and position in its 29.5-day cycle, helping users understand lunar timing for astronomy, photography, gardening, and cultural observation.
The calculator uses the lunar cycle algorithm to compute the number of days elapsed since the last new moon (the lunation number), then maps this to the corresponding phase. The illumination percentage is derived from the moon's position relative to Earth and the Sun—0% at new moon, 50% at first/last quarter, and 100% at full moon. Most calculators use astronomical data including the lunar epoch (a reference new moon date) and the mean lunar month (29.53 days) to ensure accuracy across centuries.
| Input | Result | Notes |
|---|---|---|
| 22 July 2026 | Waxing Gibbous, ~78% illuminated, 19 days into lunar cycle | Most of the moon is lit and growing towards full; ideal for lunar photography with high brightness |
| 10 August 2026 | Waxing Crescent, ~15% illuminated, 3 days into lunar cycle | Slim crescent visible after new moon; best viewing low on the western horizon at dusk |
| 31 December 2025 | Waning Crescent, ~8% illuminated, 27 days into lunar cycle | Narrow crescent; visible just before sunrise in the east; marks the end of the lunar month |
Moon phase is the visual shape (crescent, quarter, gibbous, full), while illumination percentage is how much of the visible moon is sunlit (0–100%). A waxing gibbous might be 75% illuminated; a full moon is 100%.
Modern calculators are accurate to the specific minute using astronomical algorithms. Historical dates (before 1900) and future dates (beyond 2100) may have small variances due to lunar orbit irregularities, but they're reliable within ±1 day for practical purposes.
Not directly—lunar eclipses only occur during full moons when the Earth, moon, and sun align perfectly, which is rare. This tool shows you full moon dates; you'd need to cross-reference those with eclipse prediction tables or dedicated eclipse calculators.
Yes. Full moons and new moons (when the sun, Earth, and moon align) cause the highest tides (spring tides). Quarter moons cause lower tides (neap tides). The tidal effect is stronger near coasts and larger bodies of water.
The moon orbits Earth every 27.3 days, but Earth is also moving around the sun. It takes the moon an extra ~2 days to return to the same phase relative to the sun, totaling 29.53 days (the synodic month).
Yes—the moon is visible during daylight for about half of each lunar cycle, especially during crescent and quarter phases. It's usually dim against the bright sky, but it's there.