Excel Serial Number to Date - Convert 45292 to yyyy-MM-dd Online

Cells showing 45292 or 44927 instead of dates? Those are Excel OADate serial numbers. ComTools converts them online in bulk.

Why numbers instead of dates?

Excel stores days since 1900-01-01. 45292 ≈ 2024-01-01. General format shows the serial; change format to date or use this tool for batch CSV fixes.

Convert online

Upload file, Serial → Date mode, select columns. Detects integers 1–60000 as OADate and sets display format.

Text serial numbers

Serials stored as text "45292" work with Text → Date mode too. Pure numeric columns: Serial → Date is more precise.

1904 date system

Old Mac Excel may use 1904 system. This tool uses 1900 (Windows default). Convert 1904 files in Excel first if needed.

Serial conversion tips

  • 45292 ≈ 2024-01-01, 44927 ≈ 2023-01-01
  • Decimal serials include time fraction
  • Do not select ID columns (order numbers)
  • Use Excel Format after conversion for reports