The 360 Dates Calendar or 12×30 Calendar is an administrative abstraction overlay to the Gregorian calendar and similar ones, which has 12 months with exactly 30 dates each. Every date covers 1 day at least and 2 days at most.
31 January and 1 March are part of the second month. The 31st days of May, July, August, October and December share a date with the respective 30th day.
| Month | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | X | Y |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dates | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 |
| Days | 30+ | 31 | 31 | 31 | 31 | 31 | ||||||
| Equivalent | 31 | 28+ | 31 | |||||||||
| Cognate | January | February | March | April | May | June | July | August | September | October | November | December |
In an alternative convention, the distribution differs for the fourth through seventh month to make it overall more systematically 30:31. This leads to more cases where a Gregorian date is found in a different equivalent months. The 1st days of May and July share a date with the 30th day of April and June, respectively.
| Month | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | X | Y |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dates | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 | 30 |
| Days | 30+ | 31 | 31 | 31 | 31 | 31 | ||||||
| Equivalent | 31 | 28+ | 31 | 30 | 31 | 30 | 31 | |||||
| Cognate | January | February | March | April | May | June | July | August | September | October | November | December |
The date format is zero-based like time formats usually are and also uses the colon as a separator, but to make dates and times visually distinct, the month field has a single digit, using X/x or H/h or K/k for 10 and J/j or Y/y for 11. Short or annual dates (without year) and times may be separated by a double colon. M:DD::hh:mm:ss Hours run from 00 through 47 on dates that span 2 days.
| Gregorian | 12×30 standard | 12×30 alternative |
|---|---|---|
| -01-01 | 0:00 | |
| -01-30 | 0:29 | |
| -01-31 | 1:00 | |
| -02-01 | 1:01 | |
| -02-28 | 1:28 | |
| -02-29 | 1:29 | |
| -03-01 | 1:29 | |
| -03-02 | 2:00 | |
| -03-30 | 2:28 | |
| -03-31 | 2:29 | |
| -04-01 | 3:00 | |
| -04-30 | 3:29 | |
| -05-01 | 4:00 | 3:29 |
| -05-02 | 4:01 | 4:00 |
| -05-30 | 4:29 | 4:28 |
| -05-31 | 4:29 | |
| -06-01 | 5:00 | |
| -06-30 | 5:29 | |
| -07-01 | 6:00 | 5:29 |
| -07-02 | 6:01 | 6:00 |
| -07-30 | 6:29 | 6:28 |
| -07-31 | 6:29 | |
| -08-01 | 7:00 | |
| -08-30 | 7:29 | |
| -08-31 | 7:29 | |
| -09-01 | 8:00 | |
| -09-30 | 8:29 | |
| -10-01 | 9:00 | |
| -10-30 | 9:29 | |
| -10-31 | 9:29 | |
| -11-01 | X:00 | |
| -11-30 | X:29 | |
| -12-01 | Y:00 | |
| -12-30 | Y:29 | |
| -12-31 | Y:29 | |