Time ToolsMoon Phase Calculator
Calculate the current moon phase and view the lunar calendar for any month. See illumination, moon age, and upcoming new and full moon dates.
Lunar Calendar
March 2026
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About Moon Phase Calculator
How It Works
- Select any date using the date picker or calendar
- The tool calculates the lunar age using the Julian Date system
- Moon phase is determined from a 29.53-day synodic period
- Illumination percentage is calculated from the phase angle
- The lunar calendar displays all phases for the selected month
Common Use Cases
- Planning outdoor photography sessions at full moon
- Gardening by lunar cycles for planting and harvesting
- Fishing and hunting based on moon activity
- Spiritual practices and moon rituals
- Astronomical observation planning
- Understanding tidal patterns for coastal activities
Frequently Asked Questions
How is the moon phase calculated?
The tool uses the Julian Date system to compute the number of days since a known new moon (January 6, 2000). Dividing by the 29.53-day synodic period gives the current lunar age, which maps directly to one of the eight named phases.
What are the eight moon phases?
The eight phases are: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, and Waning Crescent. Each phase lasts roughly 3.7 days.
What does moon illumination percentage mean?
Illumination percentage shows how much of the lunar surface is lit by the Sun as seen from Earth. At new moon it is 0%, at full moon it is 100%, and at the quarters it is around 50%.
What is "moon age"?
Moon age is the number of days elapsed since the last new moon. It ranges from 0 (new moon) to approximately 29.5 days (just before the next new moon).
Can I check the moon phase for any historical or future date?
Yes. Simply type a date into the date picker or click any day in the lunar calendar. The tool works for any date supported by the browser's date input.
How accurate is this moon phase calculator?
The calculation uses the mean synodic period and is accurate to within a few hours for most dates. For precise astronomical work (e.g., eclipse prediction), specialised software should be used.
Why do the moon phase emojis differ between devices?
Moon phase emojis are rendered by the operating system. Their appearance may vary slightly between devices and platforms, but the phase name and description will always be accurate.
How do I find the next full moon or new moon?
The result card shows the exact date of the next new moon and next full moon relative to the selected date. You can also browse the lunar calendar to find months when these events occur.
Is the moon phase the same worldwide?
Yes, the moon phase is identical everywhere on Earth at any given moment. The exact time of moonrise and moonset varies by location, but the phase itself is a global phenomenon.
Why does the lunar month have 29.5 days instead of a whole number?
The synodic period is 29.53058868 days because the Earth is also moving around the Sun. The Moon must travel slightly more than one full orbit to align with the Sun again, making the cycle fractionally longer than a sidereal month.
Can I use this for gardening or planting schedules?
Many gardeners follow biodynamic or lunar gardening principles, planting root crops near new moon and leafy greens near full moon. This tool lets you plan weeks or months ahead by browsing the lunar calendar.