How to Find Z Score in Excel

What this does

STANDARDIZE converts a raw value into a z-score: how many standard deviations it lies above or below the mean. That single number makes otherwise incomparable measures comparable — a test score and a response time can be ranked against each other once both are standardised. It is also the basis of the usual outlier rule, where anything beyond roughly ±3 warrants a look. The standard deviation argument must be positive; zero returns #NUM!, which happens when every value in the range is identical. 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 “find z score in 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 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

A value of 88 in a distribution with a mean of 72 and standard deviation of 9: =STANDARDIZE(88, 72, 9) returns 1.78, meaning it sits 1.78 deviations above average. Applied down a column, =STANDARDIZE(B2, AVERAGE($B$2:$B$200), STDEV.S($B$2:$B$200)) standardises the whole series and makes outliers visible at a glance. STANDARDIZE puts different measures on one scale, which is the prerequisite for comparing or combining them at all. 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. Here is the takeaway for “find z score in excel”: 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

• Forgetting to anchor the mean and standard-deviation ranges when filling down, so each row standardises against a different distribution.
• A standard deviation of zero, which returns #NUM! — every value in the range is identical.
• Reading z-scores as probabilities; converting them needs NORM.S.DIST.

Frequently asked questions