Fantasy calendar maker
Your world's own months, a week of any length, leap years and eras. Print any year, and ask what weekday a date falls on. Free, no sign-up, saved in this browser.
Make your world's calendar, or look around a finished one first.
Ask the calendar
Days between
From the date above to this one:
Months, in order
The week
Any number of days, from 1 to 20. The week runs on unbroken from one year to the next, so each year starts on the weekday after the last day of the year before.
Leap years
Eras
The same eras as the timeline maker: year 1 of each era follows the last year of the one before, and the last era runs on with no end.
Your calendar is kept in this browser only. Clearing site data deletes it; save a file to keep it, move it to another device, or give your timeline its months.
What this is
A calendar for an invented world. List its months in order, each with a name and a number of days (they need not be equal: 36, 37, 13, 90 are all fine). Name the days of its week, as many as you like. Add a leap rule if your year needs one: every N years, add D days to one month. Then pick any year and see it as month grids, one month or the whole year, and print it.
The example is the invented Saltglass Reckoning: ten months from Ashkiln to Cullet (363 days), a six-day week from Gatherday to Hearthday, and two extra days in Highfurnace every fifth year, so its average year is 363.4 days. Its eras are the Age of Kilns (380 years) and the Age of Lanterns, the same as the example on the timeline maker.
The weekday carries over. The week never restarts at New Year: in the example, Year 1 AK begins on a Gatherday, and 363 days later (60 weeks and 3 days) Year 2 begins on a Pontilday. Leap years shift it a further two.
Date arithmetic
Under Ask the calendar, type a date and see its weekday and its place in the year: 3 Glassbloom 312 AK falls on Pontilday, day 75 of a 363-day year. A second date gives the days between them, in days and in your own weeks. Every date is counted as one number of days from the first day of the first era, so the sums run across months, leap years and eras with nothing to round.
Use it in a timeline
Save file writes a .dankstory-calendar.json file. On the timeline maker, open it under Tracks and eras, and each event's editor gets a month and a day, with the weekday. Timelines saved before this existed open just as they were.
What it cannot do
One leap rule only: "every 4 years, except every 100th" cannot be written, so a copy of the real Gregorian calendar drifts by a day outside 1901 to 2099. No moons, seasons, holidays or astronomy: it does not work out phases or sky events, and it does not claim to. There are no days outside the months (no intercalary festival days that belong to no month); make them a short month instead. Day names and months are whatever you type: nothing checks them against real calendars.
Private by design
No account and no upload. The calendar is saved in this browser on every change and nothing you type leaves your device. A damaged file, a different kind of file, or one from a newer version of this page is refused with a message and never replaces your work.