convert excel date serials ↔ iso 8601 ↔ unix · 1900 & 1904 modes · accepts m/d/yyyy and unix epochs
| input | iso 8601 | excel serial | unix sec | note |
|---|---|---|---|---|
| 1 | 1899-12-31T00:00:00.000Z | 1 | -2209075200 | |
| 60 | 1900-02-27T00:00:00.000Z | 60 | -2204064000 | phantom leap day |
| 61 | 1900-02-28T00:00:00.000Z | 61 | -2203977600 | |
| 44197 | 2020-12-31T00:00:00.000Z | 44197 | 1609372800 | |
| 45292 | 2023-12-31T00:00:00.000Z | 45292 | 1703980800 | |
| 2.5 | 1900-01-01T12:00:00.000Z | 2.5 | -2208945600 |