Moon Phase Calculator - Current Moon Phase Tonight
Current moon phase, illumination and moon age for any date, plus next full and new moon.
Tool Interface
—
Phases are calculated from the mean lunar cycle of 29.53 days and may differ from exact astronomical timings by a few hours. Dates are computed for 12:00 UTC on the selected day.
How to use
- Pick a date: use the date field to choose any day, past or future.
- Calculate: press Calculate to see the moon phase for that date.
- Read the result: the moon graphic, phase name, illumination and moon age update instantly.
- Plan ahead: check the next new moon and next full moon dates shown below the graphic.
Rate this tool
About This Tool
About This Tool
The Moon Phase Calculator shows the phase of the moon for any date. Pick a day and instantly see the phase name, how much of the moon is lit, the age of the moon in days, and the dates of the next new moon and next full moon.
Key Features
- Phase name and moon graphic for any date, past or future
- Illumination percentage and moon age in days
- Next new moon and next full moon dates
- Works for tonight or for planning months ahead
- Free, private, and fully in your browser with no signup
How to Use
- Choose a date in the date field, or press Today for the current date.
- Press Calculate to update the moon graphic and results.
- Read the phase name, illumination, and moon age.
- Check the next new moon and next full moon dates to plan ahead.
Frequently Asked Questions
What is a moon phase?
A moon phase is how much of the moon appears lit from Earth as the moon orbits. The full cycle lasts about 29.53 days, from one new moon to the next.
How is the phase calculated?
The tool counts days since a known new moon on January 6, 2000, divides by the 29.53 day cycle, and derives the phase, illumination, and age from that position in the cycle.
How accurate is it?
Phases use the mean lunar cycle, so results may differ from exact astronomical timings by a few hours. That is accurate enough for planning, photography, and curiosity.
What does illumination mean?
Illumination is the percentage of the visible face of the moon that is lit: 0 percent at new moon and 100 percent at full moon.
When is the next full moon?
Pick any date and the tool shows the next full moon date from that day, along with the next new moon date.