Comprehensive Calculator Guide
The moon phase calculator tells you the moon’s phase on any date — new, crescent, quarter, gibbous or full — with its age in days, the share that’s lit and the approximate dates of the next full and new moons. On 27 October 2026 the moon is just past full, 16.3 days old and 97% lit. Useful for planning moonlit trips and for the white days of the Hijri month.
The phases and the Hijri calendar
A lunar month, new moon to new moon, averages 29.53 days: new moon, waxing crescent, first quarter around day 7, waxing gibbous, full moon around day 15, then the same steps waning.
A Hijri month begins with the sighting of the crescent after the new moon, so the moon is full mid-month. Fasting the white days — the 13th, 14th and 15th — is a Sunnah. This is an approximate astronomical figure; in Saudi Arabia the Umm al-Qura calendar and official sighting decide the months.
How to Use
- Pick a date, or leave it empty for today’s moon.
- Use a Gregorian date.
- Press “Find the phase” to see the phase, the moon’s age, how much is lit and the next full and new moons.
Formula Used
Moon age = days since a reference new moon, modulo 29.53 | Lit = (1 − cos(2π × age ÷ 29.53)) ÷ 2
Practical Examples
- Example 1
- 27 October 2026: 16.3 days old, full and starting to wane, 97% lit; next new moon about 9 November.
- Example 2
- 23 April 2024: 14.7 days, full moon.
- Example 3
- 8 April 2024, the North American total solar eclipse: new moon.
Important Tips
- For stargazing pick nights near the new moon; for night walks, near the full moon.
Common Mistakes to Avoid
- Relying on calculation alone for the start of Ramadan or Eid.
Frequently Asked Questions
- What is the moon phase today?
- Leave the date empty to see today’s phase, age and illumination.
- When is the moon full?
- About 14.8 days after the new moon, mid-way through the Hijri month.
- How long is a lunar month?
- 29.53 days on average, so Hijri months have 29 or 30 days.