COUNT Duplicates in Excel

What this does

Counting duplicates is really two questions. To see how often each value occurs, COUNTIF(A:A,A2) returns the frequency for that row — 1 means it is unique, anything higher means it repeats. To count how many distinct values a list contains, the classic =SUMPRODUCT(1/COUNTIF(range,range)) adds a fraction for each cell so every group of identical values sums to exactly 1; in Microsoft 365 the simpler =ROWS(UNIQUE(range)) does the same job. The same idea underpins a lot of everyday Excel work, so the few minutes spent getting it right here pay back across every sheet you build afterwards. Treat it as a pattern, not a one-off, and it stops being something you look up and starts being something you reach for. The difference between a quick fix and a sheet you can trust is the extra minute you spend validating “count duplicates in excel”. Start on a copy or a tiny sample, keep the affected duplicates visible, and compare the result with the tool above before you touch the real workbook. 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. The point is a data step that keeps your analysis trustworthy, but the practical win is that someone else can open the file and understand what happened without asking you.

A worked example

A column A2:A9 of fruit reads Apple, Pear, Apple, Plum, Apple, Pear, Kiwi, Plum. Put =COUNTIF(A:A,A2) beside it: Apple shows 3, Pear shows 2, Plum shows 2, Kiwi shows 1. To count the distinct fruits, =SUMPRODUCT(1/COUNTIF(A2:A9,A2:A9)) returns 4 (Apple, Pear, Plum, Kiwi), and =ROWS(UNIQUE(A2:A9)) returns the same 4 in 365. Counting duplicates answers the questions a flag cannot: how concentrated is the data, how many real customers are in a list of 5,000 rows, which value repeats most. It is the measurement step between spotting duplicates and deciding what to do about them. A practical tip before you scale it up: build it once on a small block of test data, confirm the number against the tool on this page, and only then point it at your real sheet. That one habit catches almost every mistake while it is still cheap to fix, long before a wrong figure reaches a report or a colleague.

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. 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 duplicates in 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

• Using a whole column (A:A) inside SUMPRODUCT(1/COUNTIF(...)) — the empty cells divide by zero and throw #DIV/0!; pin it to the exact range.
• Confusing the two answers: COUNTIF gives a per-row frequency, not the number of distinct values.
• Forgetting that COUNTIF is case-insensitive, so "apple" and "Apple" count as the same value.
• Letting blank cells into the distinct-count range, which the 1/COUNTIF trick cannot divide.

Frequently asked questions