🌕Moon Phase Calculator
Instantly see the current moon phase, illumination percentage, and phase name for any date. Find the next full and new moon dates.
Free moon phase calculator — aaj ka chand kaisa hai. See today's moon phase, illumination %, next full moon and new moon dates.
How to Use Moon Phase Calculator — Step by Step
- 1Select a date (defaults to today)
- 2Click 'Calculate Moon Phase' to see the current phase
- 3View the phase name, moon emoji, and illumination percentage
- 4Check the next full moon and next new moon dates
- 5The moon age shows how many days into the current 29.5-day cycle
Why Use ToolNest for Moon Phase Calculator?
- 🌕Accurate phase calculation using Jean Meeus' synodic cycle algorithm
- 💡Shows illumination percentage with a visual progress bar
- 📅Calculates next full moon and next new moon dates
- 🌑All 8 phases: New Moon through Waning Crescent with emoji icons
- 🆓100% free — works for any date, past or future
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Frequently Asked Questions
How accurate is the moon phase calculation?
Very accurate for everyday use. The tool uses the synodic cycle (29.53059 days) referenced to a known new moon epoch. Phase names and illumination are correct to within a few hours for any date from 1900–2100.
What is the synodic period of the Moon?
The Moon's synodic period — the time from one new moon to the next — is approximately 29.53059 days. This is slightly longer than the sidereal period (27.3 days) because Earth is also moving around the Sun.
What does illumination percentage mean?
Illumination percentage is the fraction of the Moon's visible disk that is lit by the Sun. 0% = new moon (dark), 50% = quarter moon, 100% = full moon.
Why do full moon dates vary each year?
Because the Moon's cycle (29.5 days) doesn't divide evenly into a calendar year (365 days). This causes full moons to drift by about 11 days earlier each year, with a 19-year Metonic cycle that returns them close to the same dates.
What is a Blue Moon?
A Blue Moon is either the second full moon in a calendar month (more common definition) or the third full moon in a season that has four full moons. They occur roughly every 2.5 years.