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Lotus 1-2-3 used an epoch from 1900-01-01, but it had a bug where it considered all years divisible by 4 to be leap years. When Excel came around, it needed to
by aidenn0 4y ago
Lotus 1-2-3 used an epoch from 1900-01-01, but it had a bug where it considered all years divisible by 4 to be leap years.
When Excel came around, it needed to be compatible with 1-2-3, so it used the same date format, and to be compatible it considers 1900 to be a leap year.
- zdw 4y agoExcel has two date systems, with either a 1900 or 1904 start date: https://support.microsoft.com/en-us/office/date-systems-in-excel-e7fe7167-48a9-4b96-bb53-5612a800b487 https://support.microsoft.com/en-us/office/date-systems-in-e... The original Excel was for the Macintosh and had the 1904 date system, and was later brought to Windows where the 1900 date system was used.
- cookingrobot 4y agoHere’s a great story about the ongoing impact of those decisions. https://www.joelonsoftware.com/2006/06/16/my-first-billg-review/ https://www.joelonsoftware.com/2006/06/16/my-first-billg-rev...