Synodic month
The Moon takes about 29.53 days to cycle through its phases relative to the Sun.
Use Moon Phase Calculator
Results appear below. Use values or text to get started.
Loading interactive tool…
Lunar cycle
A synodic month averages about 29.53 days between corresponding lunar phases. The real duration varies, so calculations based on a fixed cycle are approximate.
How to use Moon Phase Calculator
Moon Phase Calculator helps you estimate the Moon’s phase and illumination for any date. It is a simple, mobile-friendly tool available at moonphases.pages.dev. Start by entering information or choosing the action shown above, then read the result immediately.
Can I use this tool for free?
Yes. The core tool does not require payment or account registration.
What should I check before trusting the result?
Confirm your inputs and consider whether the output is an estimate. Weather, prices, medical, legal, financial and safety-related decisions require appropriate authoritative sources.
Privacy and data handling
Most calculations take place in the browser. Some tools may request public third-party information, which is described next to the relevant tool. This edition does not contain tracking scripts or advertising code.
Explore Moon Phase Calculator
Waxing and waning
Waxing means the illuminated portion is increasing as observed from Earth; waning means it is decreasing.
Accuracy
Phase calculations here approximate the mean lunar cycle. Exact illumination and rise/set times require astronomical ephemerides.