Invented Reckonings
International Fixed
13 months of 28 days · Kodak ran on it until 1989
Moses Cotsworth’s 1902 reform: thirteen months of exactly twenty-eight days, with a new month, Sol, slipped between June and July, plus a Year Day belonging to no month or week at all. Every date falls on the same weekday all year. Eastman Kodak ran its entire business on it from 1928 until 1989.
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In UTC at 02:02 on October 27, 2026, this calendar read 20 October 2026. The reading above is live, in your own time zone.
At a glance
- Type
- Solar — thirteen equal months
- Origin
- Moses B. Cotsworth, 1902
- Year
- 364 days in 13 months, plus Year Day — and Leap Day in leap years
- Months
- 13, of exactly 28 days, with Sol between June and July
- Week
- 7 days; every month starts on a Sunday
- Leap rule
- A Leap Day after 28 June, outside the week
- Counts from
- The Gregorian era
- Where it’s used
- Historical; Eastman Kodak kept it from 1928 to 1989
- How it’s worked out here
- From the Gregorian date, day by day
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