Moon Phase Today
The current lunar phase, illumination, and upcoming full and new moons — computed live in your browser. Free, fast, and nothing you enter ever leaves your device.
For interest and reflection. Phase times are computed from a mean synodic model and may differ from precise ephemeris values by up to a day near exact new and full moons.
How to read the moon phase today
- Open the page — the moon visual, illumination percentage, and phase name update instantly for the current date.
- Check the two counters to see how many days remain until the next full moon and the next new moon.
- Use the date picker to look up the moon phase for any past or future day — birthdays, weddings, camping trips, or planting schedules.
- Scroll the calendar strip to preview how the moon changes across the whole month at a glance.
Why use ZillaKit's Moon Phase tool?
This moon phase calculator runs entirely in your browser using a synodic-month model anchored to a known new-moon epoch, so it works offline, loads instantly, and never sends your dates to a server. The illumination percentage is derived from the moon's age within its roughly 29.53-day cycle, and the phase name follows the standard eight-phase convention: new moon, waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, and waning crescent. The moon visual is drawn purely with CSS and an SVG shadow mask — no images are loaded — so the terminator (the line between light and dark) shifts correctly as the phase advances. Whether you want the moon phase today, need to plan around a full moon, are curious about the sky on a meaningful date, or simply enjoy tracking the lunar cycle, everything you need is on one fast, private page with no signup and no upload.
FAQ
How accurate is the moon phase calculation?
It uses the mean synodic month (about 29.53 days) measured from a known new-moon reference, which keeps the phase name and illumination accurate to within roughly a day. It is ideal for everyday and planning use, though it is not a substitute for a precise astronomical ephemeris for scientific work.
What does the illumination percentage mean?
It is the fraction of the moon's visible disc that is lit by the sun, from 0% at a new moon to 100% at a full moon. A first or last quarter moon shows about 50% illumination even though only a "quarter" of the full cycle has passed.
Can I check the moon phase for a past or future date?
Yes. Use the date picker to select any day, and the moon visual, illumination, phase name, and calendar strip all recalculate for that date.
Why does the moon look the same for two nights in a row?
The moon's appearance changes only gradually, so consecutive nights can look nearly identical. The illumination percentage and moon age will still differ slightly, which the tool displays.
Is my date information uploaded anywhere?
No. All calculations happen client-side in JavaScript. Nothing you select is transmitted to or stored on any server.