Excel Date Converter
Convert an Excel date to a real date
A spreadsheet serial to a calendar date and back, in both the 1900 and 1904 systems — with the phantom leap day of 1900 flagged where it matters.
Questions people ask
The things that come up about excel date converters, answered plainly.
Why does my date show as 45489?
Because the cell is formatted as a number rather than a date. Excel stores dates as days since 30 December 1899, so 45489 is 16 July 2024. Changing the cell format makes it readable; this page converts it if you cannot.
What is the 1900 leap year bug?
Excel believes 29 February 1900 existed. It did not — 1900 divides by 100 but not 400, so it was a common year. Lotus 1-2-3 had the bug and Excel copied it deliberately for compatibility, which means every serial from 61 onwards is one higher than a true day count.
What is the 1904 date system?
The alternative Excel used on the Mac, counting from 1 January 1904 with no leap-year bug. Values differ by 1,462 days between the two systems, which is why a workbook that switches produces dates four years out.
Related tools
Julian days, Excel serials, GPS time, cron expressions and format validators.