How to make a moon phase calendar
- Pick one month or the whole year. The arrows step a month (or a year) at a time; any year from 1800 to 2100 works.
- Pick the time zone of the place where you'll use the calendar. It starts on your device's zone. The phase times and the dates they fall on follow that zone, daylight saving included.
- Pick how the Moon should look: Northern, Southern or Equator view (see below). It starts on the view for your time zone.
- Choose what to show and the look: full moon names, the percent lit each day, Monday or Sunday first, a 12- or 24-hour clock, four colour styles, two title fonts and an optional title of your own.
- Download the PDF and print it at 100% (actual size), or download a PNG for a phone wallpaper or a message.
How to read it
Each day shows the Moon as it is at noon in your time zone: the lit part, on the side the Sun lights it. The four principal phases are instants, the same moment everywhere on Earth: New Moon (the Moon between us and the Sun, unlit), First Quarter (half lit, growing), Full Moon (fully lit, opposite the Sun) and Last Quarter (half lit, shrinking). On the day of one of them, the calendar draws the Moon at that exact moment and prints the time beside it. The list under the preview gives every phase with its date and time, and the month page prints the same list along the bottom.
Between new and full the Moon is waxing: it rises later each day and is seen in the evening. Between full and new it is waning and is seen late at night and in the morning. A whole cycle, a lunation, takes about 29.5 days, so most months have one full Moon and every two or three years one month has two.
Northern, Southern and Equator views
The Moon's lit side always faces the Sun, but which way that is depends on where you stand. North of the tropics a waxing Moon is lit on the right ("D" for the growing Moon, "C" for the shrinking one). In Australia, New Zealand, South America and southern Africa you see the Moon the other way up, so a waxing Moon is lit on the left: the Southern view mirrors every Moon. Near the equator the Moon's path is steep, so its lit side points down or up rather than sideways: a crescent low in the sky, evening or morning, looks like a boat lit from below. No single drawing fits every hour there, so the Equator view is a convention: a quarter turn of the northern picture that keeps waxing and waning apart. Waxing Moons are lit from below, like the evening crescent in the west; waning Moons are lit from above, as the waning Moon looks rising in the east in the evening.
Full moon names and the Blue Moon
With names on, each full Moon gets the traditional North American name The Old Farmer's Almanac lists for its month, from the Wolf Moon in January to the Cold Moon in December. The Harvest Moon is the full Moon closest to the September equinox, so in some years it falls in October; the September full Moon is then the Corn Moon, and the Hunter's Moon (the one after the Harvest Moon) moves to November. A second full Moon in one calendar month is a Blue Moon: in 2026 that's May 31. Because the date depends on the time zone, a Blue Moon in one zone can be an ordinary full Moon in another.
How the phases are worked out
The times use Jean Meeus's method from Astronomical Algorithms (2nd edition, 1998, chapter 49): the average lunar cycle plus the periodic corrections for the pull of the Sun and the shape of the Moon's orbit, then converted from dynamical time to clock time. We checked all 149 phases of 2024, 2025 and 2026 against the US Naval Observatory's phase tables: every one agrees to within a minute. The lit fraction for each day comes from the Sun's and Moon's positions, the same sky engine as our star map maker, and agrees with NASA JPL's Horizons ephemeris to within one percentage point. The Northern, Southern or Equator view you start on comes from the latitude of the biggest city in your device's time zone, from GeoNames (CC BY 4.0).
Tips
- For fishing, gardening by the Moon or night photography, the month page with percent lit is the easiest to read at a glance. For a wall poster, try the whole year on 18 × 24 inches in Black & gold.
- The Ink on white style uses the least ink on a home printer.
- Need a plain wall calendar with holidays as well? Make one with the printable calendar maker. For Ramadan dates and prayer times, use the Ramadan timetable, and to see how the total solar eclipse of 2 August 2027 will look from your town, try the eclipse simulator.
- If the PDF opens at the wrong size, check your print dialog isn't set to "fit to page" or a different paper.