Lunar Phase for Any Date
Last reviewed: January 2026
Find the moon phase and lunar cycle day for any date in history or the future. This calculator runs entirely in your browser — your data stays private, and no account is required.
The Moon completes one full cycle of phases every 29.53 days (the synodic month), moving from new moon through waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, and waning crescent before returning to new moon.[1] Moon phases are caused by the changing angle between the Sun, Moon, and Earth — we see the portion of the Moon sunlit hemisphere that faces Earth, which changes as the Moon orbits. The Moon itself does not emit light; it reflects sunlight.[2] Moon phase data is essential for fishing and hunting (game activity patterns correlate with lunar cycles), photography (planning moonrise/moonset shoots), gardening (some traditions plant by lunar phases), and tidal predictions (spring tides occur at new and full moons).[3] Use the Date Calculator to count days between lunar events.
Moon phases affect ocean tides — spring tides (highest highs, lowest lows) occur at New and Full Moon when solar and lunar gravity align, while neap tides (moderate tides) occur at quarter phases. Fishermen and hunters use lunar calendars because animal feeding activity correlates with moon position and illumination. Gardeners following biodynamic or traditional methods plant different crops during waxing (above-ground crops) and waning (root crops) phases. Astronomers and stargazers plan observations around New Moon when the sky is darkest. Photographers and hikers seek Full Moon for nighttime visibility. Track other celestial events with our Sunrise & Sunset Calculator and Equinox & Solstice Calculator.
| Phase | Day of Cycle | Illumination | Rise/Set |
|---|---|---|---|
| New Moon | Day 0 | 0% | Rises/sets with Sun |
| First Quarter | Day ~7.4 | 50% (right half) | Rises noon, sets midnight |
| Full Moon | Day ~14.8 | 100% | Rises sunset, sets sunrise |
| Last Quarter | Day ~22.1 | 50% (left half) | Rises midnight, sets noon |
The Moon completes one full cycle of phases (synodic period) every 29.53 days, progressing through eight recognized phases: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter (last quarter), and waning crescent. These phases result from the changing angle between the Sun, Earth, and Moon as the Moon orbits Earth. At new moon, the Moon lies roughly between Earth and the Sun, with its illuminated side facing away from us. At full moon, Earth is between the Sun and Moon, and we see the fully illuminated face. The "waxing" phases (growing illumination) occur as the Moon moves from new to full, and the "waning" phases (shrinking illumination) occur from full back to new.
The Moon's orbital period around Earth (sidereal period) is actually 27.32 days, shorter than the synodic period. The difference exists because while the Moon orbits Earth, Earth simultaneously orbits the Sun. After 27.32 days, the Moon returns to the same position relative to the stars, but Earth has moved roughly 27° along its orbit during that time, so the Moon must travel an additional 2.21 days to reach the same Sun-Earth-Moon angle and complete the phase cycle. This distinction between sidereal and synodic periods applies to all orbiting bodies and is the reason a solar day (24 hours) differs from a sidereal day (23 hours, 56 minutes) — Earth must rotate slightly more than 360° to bring the Sun back to the same apparent position.
Tides are caused by the gravitational pull of both the Moon and the Sun on Earth's oceans, but the Moon's influence is about twice as strong as the Sun's because gravitational tidal force depends on the inverse cube of distance (not the inverse square of gravitational force). The Moon is much closer than the Sun, making its tidal effect dominant despite its much smaller mass. During full moon and new moon, the Sun and Moon align (either on the same side of Earth or on opposite sides), and their tidal forces add together, producing spring tides — the highest highs and lowest lows of the month. During first and third quarter moons, the Sun and Moon are at right angles relative to Earth, partially canceling each other's tidal forces and producing neap tides — the most moderate tidal range.
Tidal range varies enormously by geography. The Bay of Fundy in Canada experiences the world's largest tides, with ranges exceeding 50 feet (16 meters) between high and low tide due to the bay's funnel shape and natural resonance period. Mediterranean beaches experience tides of only 1-2 feet. Understanding the relationship between moon phase and tidal behavior is essential for coastal activities including fishing (many species feed more actively during tidal flow), surfing (wave shape changes with tide level), boating (shallow channels may become impassable at low tide), and coastal construction (excavation and foundation work must account for tidal water tables).
Lunar calendars predate solar calendars in most civilizations because moon phases are easy to observe and provide a natural timekeeping unit. The Islamic calendar remains purely lunar, with twelve months of 29 or 30 days totaling 354 or 355 days per year — approximately 11 days shorter than the solar year, causing holidays like Ramadan to migrate through the seasons over a 33-year cycle. The Jewish and Chinese calendars are lunisolar, adding a 13th month periodically to keep lunar months aligned with solar seasons. Easter, the most important Christian holiday, is determined by a lunisolar calculation: it falls on the first Sunday after the first full moon on or after the March equinox — a formula established at the Council of Nicaea in 325 CE.
Agricultural traditions around the world connect planting and harvesting cycles to moon phases. "Planting by the moon" — sowing above-ground crops during the waxing moon and root vegetables during the waning moon — appears in farming almanacs dating back centuries. Scientific evidence for lunar influence on plant growth is limited and controversial, but the practice persists in many gardening communities. What is well-documented is the moon's effect on animal behavior: many marine species time spawning events to specific moon phases, nocturnal predators adjust hunting patterns based on moonlight availability, and coral mass spawning events worldwide are triggered by the full moon following spring temperature thresholds.
See also: Sunrise & Sunset Calculator · Equinox & Solstice Calculator · Countdown Timer
The moon completes a full cycle in 29.53 days (synodic month). Full moon: fully illuminated. New moon: not visible. The moon
→ The lunar cycle is 29.53 days — not exactly a calendar month. This "synodic month" is the time from one new moon to the next. Because it's slightly less than 30 days, the full moon shifts 1–2 days earlier each calendar month. About every 2.7 years, two full moons occur in the same calendar month (the second is called a "blue moon").
→ Full moons rise at sunset and set at sunrise — that's geometry, not coincidence. A full moon is directly opposite the sun from Earth's perspective. As the sun sets in the west, the full moon rises in the east. First quarter moons rise at noon and set at midnight. New moons rise and set with the sun (invisible). Track related celestial events with our Sunrise-Sunset Calculator.
→ Moonlight is reflected sunlight — phase = angle between sun, moon, and Earth. At new moon, the moon is between Earth and sun (sunlit side faces away). At full moon, Earth is between sun and moon (fully illuminated side faces us). Crescent and gibbous phases are partial viewing angles. The moon doesn't generate its own light.
→ Lunar phases affect tides. Spring tides (highest highs, lowest lows) occur at new and full moons when sun and moon align gravitationally. Neap tides (moderate range) occur at quarter moons when sun and moon pull at right angles. The tidal range difference can be 20–40% between spring and neap tides.
See also: Sunrise-Sunset Calculator · Equinox & Solstice · Day of Week Calculator · Age Calculator