Pick any date from 1900 onwards
Moon awaits
Select a date and check the phase// see the moon phase for any date in one click
Find the moon phase for any date instantly. See waxing, waning, full, or new moon status with illumination percentage and lunar cycle details.
Moon awaits
Select a date and check the phaseUse the date picker or quick buttons to select today, yesterday, or tomorrow.
Click "Check Moon Phase" to instantly calculate the lunar phase for your date.
See the phase name, illumination %, lunar day, and upcoming full/new moon dates.
The Moon Phase Calculator determines the exact phase of the moon for any given date using precise astronomical algorithms. It calculates the moon's position in its 29.53-day synodic cycle and returns the phase name, illumination percentage, and upcoming key events.
The calculator uses a well-tested astronomical algorithm accurate to within a few hours. It correctly identifies the eight standard lunar phases and provides illumination percentages within ~1% accuracy for any date from 1900 onwards.
The eight phases in order are: New Moon (0%), Waxing Crescent (1–49%), First Quarter (50%), Waxing Gibbous (51–99%), Full Moon (100%), Waning Gibbous (51–99%), Last Quarter (50%), and Waning Crescent (1–49%).
A lunar synodic cycle (from new moon to new moon) takes approximately 29.53 days, or about 29 days, 12 hours, and 44 minutes. This is why full moons don't fall on the same calendar day each month.
Waxing means the moon is getting brighter — the illuminated portion is increasing from new moon toward full moon. Waning means the illuminated portion is decreasing from full moon back toward new moon.
Yes! The calculator works for any date from 1900 onwards. Simply select a past date using the date picker and click Check Moon Phase to see what the moon looked like on that day.
The phase and illumination percentage are the same worldwide, as the moon's position relative to Earth and the Sun doesn't change based on your location. However, the moon's orientation in the sky may appear flipped in the Southern Hemisphere.
The moon has fascinated humans for millennia, guiding agriculture, navigation, religious calendars, and folklore. Our Moon Phase Calculator makes it effortless to determine the exact lunar phase for any date in history or the near future, giving you the phase name, illumination percentage, current lunar day, and the dates of the next new and full moons.
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The moon goes through eight distinct phases during its approximately 29.53-day synodic cycle. Each phase represents a different geometric relationship between the Earth, Moon, and Sun, which determines how much of the moon's illuminated surface we can see from Earth.
The cycle begins with the New Moon, when the moon is positioned between Earth and the Sun, making it invisible from Earth's surface. As the moon moves along its orbit over the following days, a thin sliver becomes visible — this is the Waxing Crescent. By day 7–8, approximately half the moon is illuminated, which we call the First Quarter.
The moon continues to grow brighter through the Waxing Gibbous phase, until it reaches its peak brightness at the Full Moon around day 14–15. At this point, the Earth is positioned between the Sun and Moon, allowing us to see the entire sunlit face. The moon then begins to dim through Waning Gibbous, reaches the Last Quarter (half illuminated again), passes through Waning Crescent, and finally returns to New Moon, completing the cycle.
Calculating the moon's phase requires knowing its position within the synodic cycle. Our calculator uses an algorithm based on Julian Day Numbers — a continuous count of days used in astronomy — to determine precisely where in its cycle the moon falls on any given date.
The key metric is the phase angle, expressed as a value from 0 to 1 (or 0% to 100%), representing the moon's progress through its full 29.53-day cycle. From this angle, we can derive the illumination percentage using a cosine function, and map the angle to one of the eight named phases.
For example, a phase value of 0 or 1 means New Moon (0% illumination). A value of 0.5 means Full Moon (100% illumination). Values between 0 and 0.5 are waxing (getting brighter), while values between 0.5 and 1.0 are waning (getting dimmer).
Astrophotography and Stargazing: A new moon provides the darkest skies, making it the ideal time for deep-sky photography and viewing faint objects like nebulae and galaxies. Conversely, a full moon washes out the night sky but makes the lunar surface itself spectacular to photograph.
Gardening and Agriculture: Many gardeners follow biodynamic planting calendars that align sowing, transplanting, and harvesting with lunar phases. Root crops are traditionally planted during a waning moon, while leafy greens and fruiting plants during a waxing or full moon.
Fishing and Hunting: Fish and wildlife activity often correlates with lunar phases. Many anglers report increased fish activity around new and full moons, when tidal forces are strongest and feeding patterns change.
Event Planning: A full moon adds atmosphere to outdoor weddings, festivals, and evening events. Our calculator helps you find the ideal date with the right moon phase for your occasion.
Historical Research: Writers, historians, and researchers can look up what the moon looked like on any significant historical date, from battles and births to natural disasters and astronomical events.
The moon's cycle has been central to human culture since prehistoric times. Many of the world's major calendars are lunar or lunisolar — the Islamic Hijri calendar is purely lunar, while the Hebrew and Chinese calendars synchronize the lunar month with the solar year through periodic leap months.
Religious observances worldwide are tied to the moon: Ramadan begins with the new crescent moon, Easter falls on the first Sunday after the first full moon following the spring equinox, and Diwali is celebrated on the new moon night of Kartik. Understanding moon phases connects you to this rich cultural heritage.
It's worth noting that this calculator focuses on lunar phase — the percentage of the moon's face illuminated and visible from Earth — rather than moonrise or moonset times, which vary by geographic location and time zone. For tidal information or precise moonrise times at your location, you would need a different tool that accounts for your latitude and longitude.
The illumination percentage and phase name, however, are universal — the same full moon rises over Tokyo and Toronto, even if at different local times. This makes our calculator useful for planning anywhere in the world without needing location data.