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DATEDIF function in Excel

Calculates the number of days, months, or years between two dates. This function is useful in formulas where you need to calculate an age.

=DATEDIF(start_date, end_date, unit)

DATEDIF syntax and parameters

Three arguments, three required.

  • start_dateanyRequired

    A date that represents the first, or starting date of a given period. Dates may be entered as text strings within quotation marks (for example, "2001/1/30"), as serial numbers (for example, 36921, which represents January 30, 2001, if you're using the 1900 date system), or as the results of other formulas or functions (for example, DATEVALUE("2001/1/30")).

  • end_dateanyRequired

    A date that represents the last, or ending, date of the period.

  • unitstringRequired

    The type of information that you want returned, where:Unit****Returns"Y"The number of complete years in the period."M"The number of complete months in the period."D"The number of days in the period."MD"The difference between the days in start_date and end_date. The months and years of the dates are ignored.Important: We don't recommend using the "MD" argument, as there are known limitations with it. See the known issues section below."YM"The difference between the months in start_date and end_date. The days and years of the dates are ignored"YD"The difference between the days of start_date and end_date. The years of the dates are ignored.

DATEDIF examples

Formulas you'll actually reuse.

  1. Age in whole years from a birthday in B2:

    =DATEDIF(B2, TODAY(), "Y")

  2. Tenure spelled out — 15 Jan 2026 to 3 Sep 2026 with the Y, YM and MD units:

    =DATEDIF(A2, B2, "Y") & " years, " & DATEDIF(A2, B2, "YM") & " months, " & DATEDIF(A2, B2, "MD") & " days"

    Result"0 years, 7 months, 19 days"

DATEDIF in Google Sheets

Same name — your formula ports as-is.

Try DATEDIF in the playground

Edit the example — nothing to install.

Preloaded with the DATEDIF formula from Example 1 — change anything and watch it respond.

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DATEDIF errors

What they mean — and the fixes.

  • #NUM!

    The end date is earlier than the start date, or the unit isn't one of Y, M, D, MD, YM, YD.

Related functions

More ways Excel gets this done.