Excel SUM by UNIQUE Value

What this does

UNIQUE is a dynamic-array function in Excel 365 and Excel 2021 that returns the distinct values from a range, spilling the live result into the cells below. Unlike the Remove Duplicates data tool — a one-off action that permanently edits your data — UNIQUE is a formula that recalculates whenever the source changes, so a dropdown or report stays current. The optional by_col switches it to compare columns instead of rows, and exactly_once returns only the items that occur a single time. Because it spills, it needs empty cells below; if something blocks the spill it returns a #SPILL! error. 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. Treat “excel sum by unique value” 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 data step that keeps your analysis trustworthy into a method you can reuse, explain, and defend when the workbook leaves your screen.

A worked example

Region names with repeats sit in A2:A100. =UNIQUE(A2:A100) spills a clean list of each region once — say West, East, North, South — into the cells below the formula. To list only regions that appear exactly once, add the third argument: =UNIQUE(A2:A100, FALSE, TRUE). To sort the distinct list, wrap it: =SORT(UNIQUE(A2:A100)). UNIQUE is the modern way to build live distinct lists — for dashboards, dropdowns and summaries — because it updates automatically and, unlike Remove Duplicates, never alters the underlying data. 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. The aim was to get you unstuck fast and leave you a little more capable than a copy-paste would. The answer is at the top, the tool proves it, and the detail above shows why it holds — so the next time a colleague asks, you can answer without reaching for search. Here is the takeaway for “excel sum by unique value”: copy the answer if you are busy, but if you have a spare few minutes, rebuild the example in Excel yourself with the tool above open beside it. That single pass — type it, run it, watch the result move when you change an input — is what turns a formula you found into a technique you trust. Keep your inputs labelled and referenced, never hard-coded, and the same sheet stays correct and auditable as it grows. Done that way, you will not need to look this up again, and you will be the person others ask.

Common mistakes

• Placing the formula where cells below are occupied, which blocks the spill and returns a #SPILL! error — clear the range underneath.
• Confusing UNIQUE with Remove Duplicates — Remove Duplicates is a one-off tool that deletes data, while UNIQUE is a live formula that leaves the source intact.
• Using UNIQUE in Excel 2019 or earlier, where it does not exist and returns #NAME?; fall back to Remove Duplicates or an advanced filter there.

Frequently asked questions