Dates stored as numbers
Excel Date Serial Converter
Convert an Excel serial number to a calendar date, or a calendar date back to a serial number. Choose the 1900 or 1904 date system explicitly.
Serial → date
Result appears here.
Date → serial
Result appears here.
About the 1900 leap-year quirk
Excel's 1900 date system preserves a historical compatibility quirk around serial 60. CellLingo labels that special value rather than pretending it represents a normal Gregorian date. The 1904 date system uses a different epoch and is offset from the 1900 system.