Today's moon phase, illumination percentage and lunar cycle details. Check any date.
The moon's appearance changes predictably through a 29.5-day cycle from new moon to full moon and back. This tool calculates the current moon phase for any date and gives you the illumination percentage and the days until the next new or full moon.
Moon phases matter for gardeners using lunar planting calendars, for fishing (many species feed more actively around the full moon), for photographers planning shots, and for anyone who simply enjoys paying attention to the night sky.
The calculation is astronomical — based on the actual lunar cycle — and accurate to within a few hours for any date past or future.
New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Third Quarter, and Waning Crescent. The cycle then repeats. Each phase lasts approximately 3-4 days, with the full transition taking 29.5 days.
The scientific evidence for strong behavioural effects in humans is limited — most well-designed studies don't support the popular belief that full moons cause unusual behaviour. However, the full moon does affect ocean tides, and many fish and marine species have biological rhythms tied to the lunar cycle.
A supermoon occurs when a full moon coincides with the moon being near the closest point in its elliptical orbit (perigee). The moon appears slightly larger and brighter than average — typically about 7-14% larger in apparent diameter. The difference is real but often less dramatic than media coverage suggests.
In modern usage, a blue moon is the second full moon in a calendar month, which happens roughly every 2.5 years. The phrase 'once in a blue moon' predates this astronomical use — the older definition referred to the third full moon in a season that has four.