Discover the current phase of the Moon for any date. Track lunar cycles, illumination percentages, and upcoming celestial events.
Last updated: March 2026
Moon phases are the different appearances of the Moon as seen from Earth, caused by the changing positions of the Moon, Earth, and Sun. As the Moon orbits Earth over approximately 29.5 days, the amount of its sunlit surface visible from Earth changes, creating the distinct phases we observe.
The lunar cycle progresses through eight major phases: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, and Waning Crescent. During a New Moon, the Moon is positioned between Earth and the Sun, making its illuminated side face away from us. At Full Moon, Earth is between the Sun and Moon, allowing us to see the entire illuminated face.
Understanding moon phases has been crucial throughout human history for agriculture, navigation, religious observances, and cultural celebrations. Today, moon phases continue to interest astronomers, photographers, gardeners, and anyone fascinated by celestial mechanics.
π Approximation Note
This calculator uses a simplified astronomical algorithm based on a fixed synodic month (29.53 days) and a single reference New Moon date (January 6, 2000). Results are accurate for casual use and educational purposes but should not be relied upon for professional astronomical work. For precise astronomical calculations, consult official ephemeris data or astronomical software. Phase predictions may drift by Β±1-2 days over extended time periods.
Our calculator uses astronomical algorithms to determine moon phases:
β οΈ Accuracy Limitations
This simplified algorithm uses a constant synodic month (29.53 days) and does not account for orbital perturbations, precession, or lunar acceleration. Actual lunar phases vary by Β±1-2 days depending on orbital mechanics. Next Full/New Moon predictions assume fixed 14.77-day intervals, which oversimplifies real lunar dynamics. For precise dates, use astronomical ephemeris software (e.g., NASA JPL HORIZONS, timeanddate.com).
Moon is between Earth and Sun
Moon is becoming more visible
Half of the Moon is illuminated
More than half illuminated
Entire face is illuminated
Illuminated portion decreasing
Half illuminated, opposite side
Thin crescent before new moon
Let's calculate the moon phase for March 18, 2026:
A complete lunar cycle (synodic month) takes approximately 29.53 days, from one New Moon to the next. This is slightly longer than the Moon's orbital period (27.3 days) because Earth is also moving around the Sun.
Moon phases occur because the Moon orbits Earth while both orbit the Sun. We see different portions of the Moon's sunlit side depending on its position relative to Earth and the Sun. The Moon doesn't generate its own lightβwe see reflected sunlight.
A Blue Moon is the second Full Moon occurring in a single calendar month. Despite the name, the Moon doesn't actually appear blue. This phenomenon happens about once every 2-3 years due to the mismatch between calendar months and lunar cycles.
A Super Moon occurs when a Full Moon coincides with the Moon's closest approach to Earth (perigee). The Moon can appear up to 14% larger and 30% brighter than when it's at its farthest point (apogee).
Yes! Moon phases directly influence tides. During Full Moon and New Moon (syzygy), the Sun and Moon align, creating stronger 'spring tides' with higher highs and lower lows. During quarter phases, we get weaker 'neap tides.'
The Moon is tidally locked to Earth, meaning its rotation period matches its orbital period. This synchronous rotation keeps the same hemisphere facing Earth at all times. The far side (not 'dark side') is never visible from Earth.
Lunar age is the number of days that have elapsed since the last New Moon. It ranges from 0 (New Moon) to about 29.5 days (next New Moon). This helps determine the current phase and predict upcoming phases.
Despite popular belief, scientific studies have found no reliable evidence that moon phases significantly affect human behavior, sleep patterns, or birth rates. However, the Moon's phases remain culturally significant worldwide.
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