In Excel: use =DATEDIF(start_date, end_date, "d") — it returns the difference between two dates in the unit you ask for: "d" for days, "m" for whole months or "y" for whole years.
Syntax
Arguments
| Argument | Description | |
|---|---|---|
start_date | required | The earlier date — the start of the period. |
end_date | required | The later date — the end of the period; it must not be earlier than start_date. |
unit | required | The unit in quotes: "d" days, "m" whole months, "y" whole years, plus "ym", "yd" and "md" for the leftover part. |
Related functions
Breakdown: 0 years · 11 months · 30 days
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What this does
DATEDIF returns the gap between two dates measured in whole days, months or years, depending on a unit code you give in quotes. Beyond the basic "d", "m" and "y", three combination codes return only the remainder: "ym" the months ignoring whole years, "yd" the days ignoring whole years, and "md" the days ignoring whole months. It is most famous for age calculation — =DATEDIF(DOB, TODAY(), "y") gives a person's age in completed years. DATEDIF is an UNDOCUMENTED legacy function: it does not appear in Excel's function list and gives no autocomplete, but it works in every version. Notably the unit codes stay as the English letters "y", "m" and "d" even in German Excel. Most people learn this as a sequence of clicks and forget it by next week; learning it as a pattern instead is what lets you apply it to the next, slightly different version of the problem without starting from scratch. That is the difference this page is trying to make. Treat “calculate days between two dates excel” as a small repeatable workflow rather than a one-off click you hope to remember next time. Use a small test block before the live file, so any surprise in the affected cells shows up while it is still harmless. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. That turns a calculation you can defend to a CFO or an auditor into a method you can reuse, explain, and defend when the workbook leaves your screen.
A worked example
A start date 15/03/2020 sits in A2 and an end date 03/06/2026 in B2. =DATEDIF(A2, B2, "y") returns 6 (whole years), =DATEDIF(A2, B2, "m") returns 74 (whole months), and =DATEDIF(A2, B2, "d") returns 2271 (days). For an exact age string, combine units: =DATEDIF(A2, B2, "y") & " years, " & DATEDIF(A2, B2, "ym") & " months" returns "6 years, 2 months". For a live age, use TODAY() as the end date. DATEDIF is the simplest way to get a clean whole-number difference in years, months or days — the standard tool for ages, tenure and durations across every Excel version. If there is any chance you will reuse this, drop it into a small template tab right now: a labelled input area on the left and the formula beside it, checked once against the tool above. Next time the same question comes up, the answer is a single paste away instead of a rebuild from memory.
In Google Sheets
Everything above works in Google Sheets too. Excel and Sheets share the formula syntax used here; only the surrounding menus are arranged differently. That portability is deliberate — learn it once and it follows you between the two tools and across Windows and Mac. Nothing on this page is behind a login: the tool runs entirely in your browser, the formula is shown in full with one-click copy, and the steps work the same on Windows and Mac. That is the whole promise here — the exact answer, a way to prove it on your own numbers, and just enough context to make it stick. If you take one thing from this page on “calculate days between two dates excel”, make it the habit rather than the keystrokes: set the problem up with labelled inputs, reference those cells, and let Excel do the recomputing. Bookmark the page for the syntax, but do the example once in a blank sheet and check it against the tool above — five minutes of hands-on practice fixes the method in memory far better than re-reading, and it surfaces the small snags while they are still harmless. After that the technique is genuinely yours: faster than searching for it again, and reliable enough to drop into work that other people depend on.
Common mistakes
- Putting the dates in the wrong order — start_date must be the earlier date, or
DATEDIFreturns a#NUM!error. - Expecting "d" to count only working days —
DATEDIFcounts every calendar day; for weekdays useNETWORKDAYSinstead. - Translating the unit codes in German Excel — they stay as the English letters "y", "m" and "d"; only the argument separator changes to a semicolon.
Frequently asked questions
Why is DATEDIF not in the function list?
DATEDIF is an undocumented legacy function kept for Lotus 1-2-3 compatibility, so Excel offers no autocomplete or wizard for it. You must type it in full, but it calculates correctly in every version.
How do I calculate age with DATEDIF?
Use the "y" unit with TODAY() as the end date: =DATEDIF(DOB, TODAY(), "y") returns the age in completed years. Add "ym" and "md" parts if you want years, months and days.
Do the unit codes change in German Excel?
No. The unit codes stay as the English letters "y", "m" and "d" even in a German installation; the function name also stays DATEDIF, and only the argument separator becomes a semicolon: =DATEDIF(A2; B2; "y").
Other ways people ask this
People reach this page typing “calculate the days between two dates in excel”, “how to calculate days between two dates in excel”, “excel formula calculate days between two dates” and “excel formula to calculate days between two dates”, among other phrasings; whichever wording you used, the fix above is the one you want.
Why do people search for this in so many different ways?
Because the same task has many names. “calculate the days between two dates in excel”, “how to calculate days between two dates in excel”, “excel formula calculate days between two dates” all point at the one operation explained on this page, which is why they all lead here.