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About this tool
See today's moon phase, illumination and age, plus a full monthly calendar and upcoming new and full moon dates.
Moon Phase Today & Calendar reports the current phase name, the illuminated fraction of the disc as a percentage, and the moon's age in days since the last new moon, computed with the astronomy-engine ephemeris rather than an approximation of the 29.53-day cycle. Alongside it sits a month grid drawing every day's phase with its illumination, and the dates and clock times of the next new moon, first quarter, full moon and last quarter. It is for anyone planning around moonlight — a night shoot, a stargazing session, a fast or festival date — who needs the real figure for a specific day rather than a rough phase name.
Open Moon Phase Today & Calendar on AltFTool — it loads instantly in your browser.
Open the page — it reads your device's current date and shows tonight's phase name, the Illumination percentage to one decimal, and the Moon age in days.
Step through the grid with the Previous month, Today and Next month buttons; each cell shows the phase at local noon and days holding the exact instant are badged Full or New.
Read Upcoming moon events for the next new moon, first quarter, full moon and last quarter with local times, then press Copy summary.
Phase angle and illuminated fraction come from an astronomical calculation for the exact moment, so the figure holds up against an almanac instead of drifting.
Every day in the grid is drawn with its own lit shape and illumination percentage, and the new and full moon days are marked, so the cycle is readable at a glance.
The upcoming new moon, first quarter, full moon and last quarter are each given with a date, a local time and a countdown in days.
The page reads your device's current date and returns the phase name, the percentage of the disc that is lit and the moon's age in days since the last new moon. Ages run from 0 at new moon to about 29.53 days when the next one begins, with the full moon falling near day 14.8.
Illumination is the exact fraction of the visible disc that is sunlit — it changes every hour — while the phase name is a band. A phase is labelled new, first quarter, full or last quarter only when the moon is within 6.1 degrees of that exact alignment; everything in between is called a crescent or gibbous.
The events panel searches forward from today for each of the four principal phases and lists them in date order with the local clock time and a countdown such as 'in 9 days'. Because the search runs from the current moment, the next full moon is shown whether it falls this month or next.
29.53 days on average — the synodic month, used here as 29.530588853 days. Individual cycles vary by several hours either side because the Moon's orbit is elliptical, which is why the tool gives each event a computed time instead of adding a fixed interval.