COUNT Number of Days Between Two Dates Excel

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. Keep the inputs visible and clearly labelled and the whole thing stays auditable — anyone who opens the file later, including you, can see at a glance exactly what feeds the result and change one assumption without hunting through the formula. For “count number of days between two dates excel”, the reliable version is a short checking loop, not just the first command that appears to work. Run it on a deliberately small range first, watch how the affected cells change, and only then apply the same setup to the full sheet. 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 is what makes a calculation you can defend to a CFO or an auditor useful in real work: repeatable, auditable, and not dependent on memory or luck.

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. One habit worth forming early: name the cells that hold your inputs, so the formula reads in plain language instead of a string of cell addresses. A reviewer — or you in three months — can then follow the logic without decoding what B7 and D2 were supposed to mean, which is most of what makes a sheet maintainable.

In Google Sheets

If you are in Google Sheets rather than Excel, the good news is that the formula shown here is identical and the workflow barely changes — menus sit across the top instead of in a ribbon, and a few function names differ slightly, but anything you build here moves across with little or no rework. Keep this page bookmarked for the next time the same question comes up. Better still, rebuild the example once in your own sheet — doing it yourself, with the tool above to check against, is what turns a copied formula into a technique you own. The short version of “count number of days between two dates excel”: the answer is at the top of this page, the tool proves it on your own numbers, and the sections above explain why it holds so the next variation does not stump you. Excel rewards people who reference cells instead of typing values and who keep inputs separate from formulas, because that is what makes a result you can audit months later. Build it once, deliberately, with the live tool as a check, and you convert a one-off lookup into a reusable skill — which is the whole point of learning the why and not just the what.

Common mistakes

• Putting the dates in the wrong order — start_date must be the earlier date, or DATEDIF returns a #NUM! error.
• Expecting "d" to count only working days — DATEDIF counts every calendar day; for weekdays use NETWORKDAYS instead.
• 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