Excel Date Converter
Turn a date and time into the number Excel stores, or turn an Excel serial number back into a date, in the Windows (1900) or Mac (1904) date system.
Optional. Adds the time as a fraction of a day.
Pick a date to see its Excel number.
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How to use the Excel Date Converter
Choose Excel number to date or Date to Excel number.
Pick the Excel date system, Windows (1900) or Mac (1904).
Enter the serial number, or the date and optional time.
Copy the result.
Questions about the Excel Date Converter
Excel stores dates as serial numbers, counting days from 1 January 1900 in its Windows system. A cell shows a number when it is not formatted as a date, and this tool turns that number into a date.
Choose Excel number to date and enter the serial number. Choose Windows (1900) or Mac (1904) to match the file, since the two systems count from different start dates.
Choose Date to Excel number and pick the date. Add a time if you want, and it is added as a fraction of a day.