The Excel SQRT function returns the positive square root of a number. It is the quickest way to take a square root — just remember the input must not be negative.
Syntax
| Argument | Description | |
|---|---|---|
number | Required | The number whose square root you want. Must be zero or positive; a negative number returns an error. |
How to use it
SQRT returns the non-negative square root of its argument:
It is equivalent to =POWER(n,0.5) or =n^0.5, just shorter and clearer. For the square root of π times a number, use the dedicated SQRTPI.
Negative inputs error out. =SQRT(-4) returns a #NUM! error because the result is not a real number. If the value might be negative, wrap it in ABS — =SQRT(ABS(-4)) = 2 — or test the sign first.
Try it: interactive demo
Pick a SQRT example to see the formula and its result.
Practice workbook
Frequently asked questions
Why does SQRT return a #NUM! error?
=SQRT(-4) errors. Use =SQRT(ABS(value)) if you only need the magnitude.Is SQRT the same as raising to the power 0.5?
=SQRT(25), =POWER(25,0.5), and =25^0.5 all return 5. SQRT is just the clearest to read.How do I get the square root of a negative number's magnitude?
=SQRT(ABS(-9)) returns 3. Excel has no built-in real square root for negatives.What is the square root of 2 in Excel?
=SQRT(2) returns about 1.4142135623731 — the full 15-digit precision Excel stores.Master functions like this in one day
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