How to Insert Square Root in Excel

What this does

SQRT returns the positive square root of a number. It errors with #NUM! on negative input rather than returning a complex result, which is why the common defensive form is =SQRT(ABS(A2)) when the sign is known to be noise. In statistics it is the step that turns a variance into a standard deviation, and it appears in distance and standard-error formulas for the same reason. It is equivalent to =POWER(A2, 0.5), but SQRT states the intent plainly. 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 “insert square root in 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 layout choice that keeps the sheet readable and sortable useful in real work: repeatable, auditable, and not dependent on memory or luck.

A worked example

Converting a variance of 18.49 into a standard deviation: =SQRT(18.49) returns 4.3. Standard error from a standard deviation of 12 across 36 observations: =12/SQRT(36) returns 2. Straight-line distance between two points: =SQRT((x2-x1)^2 + (y2-y1)^2). SQRT is the step that converts squared quantities back into the original units, which is why every standard deviation and distance formula ends with it. 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

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. 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. If you take one thing from this page on “insert square root in 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

• Passing a negative number, which returns #NUM! — Excel has no real square root for it.
• Taking the square root of a sum where each term needed squaring first; the squares go inside the brackets.
• Using SQRT where a different root was meant — a cube root needs =POWER(A2, 1/3).

Frequently asked questions