Moon Phase Calculator
Calculate the exact phase of the Moon, illumination percentage, lunar age, and geocentric distance for any date. Input coordinates or select a city preset to view local moonrise and moonset times, browse upcoming major phases, and explore the interactive monthly lunar calendar grid. Free, private, and no signup required.
🌒 Waxing Crescent
June 18, 2026
“A sliver of the Moon is now illuminated on the right side (Northern Hemisphere). The Moon is growing toward First Quarter.”
Tip: Click on any day in the monthly grid above to display its detailed lunar metrics, distance, and rise/set times instantly in the main dashboard.
Why Use Our Moon Phase Calculator?
Jean Meeus Algorithm Precision
Uses mathematically exact algorithms from Meeus' Astronomical Algorithms for all lunar cycles and illumination. The moon phase calculator is accurate to ±1% illumination and within half a day for major phase dates.
Secure Moon Phase Calculator Online
Your date and location data never leave your browser. The moon phase calculator runs 100% client-side — no coordinates, no dates, and no search history are ever sent to a server.
Moon Phase Calculator — No Installation
Use the moon phase calculator directly in any modern browser. No app download, no plugin, and no account required. Works on desktop and mobile — enter a date and get instant lunar data.
100% Free with Full Lunar Metrics
The moon phase calculator is completely free with no signup or usage limits. Get illumination, age, geocentric distance, angular diameter, supermoon status, moonrise and moonset times, and an interactive monthly calendar grid.
Common Use Cases for Moon Phase Calculator
Stargazing & Astrophotography
Identify New Moon dates when the sky is darkest for deep-sky imaging. Use the moon phase calculator to plan sessions around minimal lunar interference for the best results.
Tidal & Marine Activities
Check Full and New Moon dates to predict spring tides and neap tides. The moon phase calculator helps sailors, anglers, and coastal explorers time their outings safely.
Gardening & Agriculture
Follow traditional biodynamic and lunar planting guides. Use the moon phase calculator to track waxing and waning phases for scheduling seed sowing, transplanting, and pruning.
Cultural & Religious Calendars
Many global festivals — Ramadan, Diwali, Easter, Lunar New Year — are tied to specific lunar phases. The moon phase calculator lets you verify exact lunar dates for any year.
Astronomy & Education
Students and educators can use the moon phase calculator to visualize the synodic cycle, explore Meeus-based calculations, and understand key concepts like perigee, apogee, and supermoons.
Event Planning & Personal Rituals
Choose meaningful dates for weddings, ceremonies, or personal milestones. The moon phase calculator lets you pinpoint Full Moons, New Moons, and quarter phases for any date in history or the future.
Understanding Moon Phase Calculation
What is Moon Phase Calculation?
Moon phase calculation determines where the Moon sits in its synodic cycle— the 29.53-day period from one New Moon to the next. Because the Earth orbits the Sun while the Moon orbits Earth, the Moon's illuminated face changes angle continuously as seen from the ground. A moon phase calculator converts a calendar date into a precise fraction of that cycle and maps it to one of the eight named phases: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, and Waning Crescent.
How Our Moon Phase Calculator Works
- Input your date: Select any date from year 1 AD to 9999 AD using the quick date picker, manual month/day/year selectors, or the interactive monthly calendar grid. Optionally enter coordinates or choose a city preset for local moonrise and moonset times.
- Instant browser-based processing:Click any date cell or adjust the selectors and the moon phase calculator computes results immediately using Jean Meeus' Astronomical Algorithms entirely in your browser. No data is sent to any server.
- View and explore output: The main dashboard displays phase name, illumination percentage, lunar age, geocentric distance, angular diameter, supermoon status, moonrise/moonset times, and a timeline of the next four major phases. The monthly calendar grid shows the emoji and illumination for every day of the selected month.
What the Moon Phase Calculator Computes
- Synodic fraction and illumination:Derived from the Moon's elongation angle using Meeus Chapter 48 perturbation corrections, giving illumination accurate to ±1%.
- Geocentric distance and angular diameter:Calculated from the Moon's orbit perturbations, ranging from ~356,400 km (perigee) to ~406,700 km (apogee). Angular diameter is derived directly from distance and the Moon's mean radius of 1,737.4 km.
- Supermoon status: Flagged when the geocentric distance is under 365,000 km at or near a Full or New Moon, when the Moon appears up to 14% larger than average.
- Moonrise and moonset times:Approximated from the Moon's declination and hour angle for user-specified coordinates, corrected for parallax and the 0.833° horizon dip, accurate to within approximately ±15 minutes at mid-latitudes.
The Synodic Cycle, Perigee, and Apogee
The Moon's orbit around Earth is an ellipse, not a perfect circle. Its closest point — perigee — brings it to roughly 356,400 km, while the farthest — apogee — sits around 406,700 km. A Full Moon near perigee is called a Supermoon, appearing visibly larger and 30% brighter than a Full Moon at apogee. The moon phase calculator computes distance for every query and flags supermoon dates automatically, so you never need to look up a separate table.
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Frequently Asked Questions About Moon Phase Calculator
A Moon Phase Calculator is an online tool that computes the exact phase of the Moon for any calendar date. Enter a date and the moon phase calculator instantly returns the phase name (e.g., Full Moon, Waxing Crescent), illumination percentage, lunar age in days, geocentric distance, angular diameter, supermoon status, and approximate local moonrise and moonset times.
This moon phase calculator uses Jean Meeus's Astronomical Algorithms with solar and lunar anomaly corrections. Illumination percentage is accurate to within ±1%, major phase dates are precise to within half a day, and distance calculations account for the main orbital perturbations. This makes it highly reliable for stargazing, cultural planning, and biodynamic gardening.
The lunar cycle progresses in this order: 1) New Moon, 2) Waxing Crescent, 3) First Quarter, 4) Waxing Gibbous, 5) Full Moon, 6) Waning Gibbous, 7) Last Quarter, and 8) Waning Crescent. The cycle then repeats starting with a new lunation. The complete synodic cycle takes 29.53 days on average.
A Supermoon occurs when a Full Moon (or New Moon) coincides with the Moon's closest approach to Earth — perigee. The Moon's orbit is elliptical, ranging from about 356,400 km (perigee) to 406,700 km (apogee). Near perigee, the Moon can appear up to 14% larger and 30% brighter than an average Full Moon. This moon phase calculator flags any date where the geocentric distance falls under 365,000 km.
Because the Moon orbits Earth in the same direction Earth rotates, it takes the planet slightly longer to realign with the Moon each day. As a result, moonrise and moonset shift approximately 50 minutes later each day on average. This moon phase calculator accounts for your latitude, longitude, and timezone offset when estimating local rise and set times.
Coordinates are only needed to calculate local moonrise and moonset times. All other outputs — phase name, illumination, lunar age, distance — are geocentric values that are the same for every observer on Earth. You can leave coordinates at zero for phase-only results, or select a preset city or enter custom coordinates for rise/set times.
No. All date and location inputs are processed entirely within your browser. This moon phase calculator runs 100% client-side — no coordinates, no query dates, and no personal data are ever transmitted to a server or stored anywhere.
Yes. The moon phase calculator is 100% free with no signup, no account, no usage limits, and no premium tiers. Access lunar phase data for any date from year 1 AD to 9999 AD, browse the interactive monthly calendar grid, and get moonrise/moonset times for any location — all at zero cost.
Yes. The moon phase calculator supports any date from 1 AD to 9999 AD using the manual year/month/day selectors or the HTML date picker (which works within browser limits). For historical dates outside the browser date picker range, use the manual selectors to type any year directly.