Math function
Excel SQRT function
SQRT returns the square root of a number, so SQRT(81) is 9. It turns up in geometry, statistics and finance. The number must not be negative, or Excel returns #NUM!.
=SQRT(number)Arguments
number- The number you want the square root of. Must be 0 or greater.
SQRT examples
Every result below was calculated from this sample sheet by the same spreadsheet engine the Cellwise app uses.
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Room | Area (sq ft) | Width (ft) | Length (ft) |
| 2 | Bedroom | 144 | 12 | 12 |
| 3 | Office | 110.25 | 9 | 12.25 |
| 4 | Patio | 225 | 9 | 25 |
Result: 12
A square room of 144 sq ft is 12 feet on each side.
Result: 15.200740114
Pythagoras: the diagonal across the office, corner to corner.
Result: 7
Wrap a negative number in ABS first if you want the root of its size.
Result: #NUM!
A negative number has no real square root, so Excel returns #NUM!.
How to use SQRT
- Click an empty cell.
- Type =SQRT(
- Select a cell or type a number or calculation.
- Close the bracket and press Enter.
Common SQRT mistakes
Negative input
SQRT returns #NUM! for any number below zero. Use ABS inside it, or check your data.
Looking for a cube root function
There is no CBRT in Excel. Use =A1^(1/3) or =POWER(A1,1/3).
Text that looks like a number
A cell containing text like "abc" gives #VALUE!. Clean the input first.
SQRT FAQ
How do I do a square root in Excel?
Use =SQRT(A1), or raise to the power of one half with =A1^0.5. Both give the same result.
How do I calculate a cube root in Excel?
Use =A1^(1/3) or =POWER(A1,1/3). For the nth root use 1/n as the power.
Why does SQRT return #NUM! in Excel?
The number is negative. Square roots of negatives are not real numbers, so Excel refuses. Use ABS if you only need the size.
Related functions
Updated