Moon Phase Calculator
About Moon Phase Calculator
What Is a Moon Phase Calculator?
A moon phase calculator determines the phase of the moon for any given date. The moon goes through a complete cycle of phases every 29.53 days (a synodic month), transitioning from new moon through waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, third quarter, and waning crescent. This information is used by gardeners for planting schedules, fishermen for tide predictions, photographers for night sky planning, and astronomers for observation planning.
The Eight Moon Phases
The lunar cycle has eight recognized phases: New Moon (0% illuminated), Waxing Crescent (1-49%), First Quarter (50% right side), Waxing Gibbous (51-99%), Full Moon (100%), Waning Gibbous (99-51%), Third Quarter (50% left side), and Waning Crescent (49-1%). The cycle then repeats. The terms waxing (growing) and waning (shrinking) describe whether the illuminated portion is increasing or decreasing.
How to Use This Calculator
Enter a date (or use today's date) and click Calculate. The result shows the moon phase name, a visual representation of the moon's appearance, the illumination percentage, and the dates of the next full moon and new moon. A monthly calendar view shows all phases for the selected month.
Frequently Asked Questions
How long is a lunar cycle?
A complete lunar cycle (synodic month) is approximately 29.53 days, which is the time from one new moon to the next.
What is a supermoon?
A supermoon occurs when a full moon coincides with the moon being at its closest point to Earth in its orbit. The moon appears about 14% larger and 30% brighter than when at its farthest point.
Does the moon phase affect tides?
Yes. Full and new moons produce spring tides (highest highs and lowest lows) because the sun and moon's gravitational pulls align. Quarter moons produce neap tides with less tidal range.
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