Moon Phase Calculator
Discover the moon phase for any date with a beautiful visual display. See illumination percentage, moon age, and upcoming lunar events.
Moon Phase Calculator
Discover the moon phase for any date with a visual display
Understanding Moon Phases
The Moon goes through a complete cycle of phases approximately every 29.5 days. Each phase has its own characteristics and cultural significance:
How to Use
- 1Select a date — Choose the date you want to check the moon phase for using the date picker.
- 2View the moon phase — See the visual representation of the moon and its current phase name.
- 3Check illumination — View the percentage of the moon that is illuminated.
- 4See upcoming phases — Find out when the next full moon and new moon will occur.
Frequently Asked Questions
How accurate is this moon phase calculator?
Our calculator uses astronomical algorithms based on the synodic month (29.53 days) and a known new moon reference date. It provides accurate moon phase information for any date within several centuries.
What is a synodic month?
A synodic month is the time it takes for the Moon to complete one full cycle of phases (from new moon to new moon), which is approximately 29.53 days.
What are the 8 phases of the moon?
The 8 phases are: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, and Waning Crescent.
Why does the moon have phases?
Moon phases occur because we see different portions of the Moon's illuminated surface as it orbits Earth. The Sun always illuminates half of the Moon, but we see varying amounts of that lit portion depending on the Moon's position.
How long does each moon phase last?
Each of the 8 phases lasts approximately 3.7 days. The four primary phases (New, First Quarter, Full, Last Quarter) are instantaneous moments, while the intermediate phases span the time between them.