Square Root on a Calculator
Calculate square, cube, or nth roots and see a key sequence that also works when a calculator has no dedicated root key. Every answer includes a power check.
Written and checked by TheToolNet Editorial Team · Last reviewed: September 19, 2026
Square and nth root calculator
How to use the square-root key
On many scientific calculators, press √, type the number, close the template if needed, and press equals. On models that expect the number first, enter the number and then √. Test with √9 = 3 to identify the sequence used by your model.
If there is no √ key, use the power key: N1/2. For cube roots use N1/3; for an nth root use N1/n. Put the reciprocal exponent in parentheses so the calculator does not evaluate in the wrong order.
Check a root result
Raise the result to the root degree. If √144 = 12, then 12² = 144. A rounded irrational root will return a number very close to the original rather than exactly equal because the display stores limited digits.
Frequently asked questions
Can I take a square root of a negative number?
Not in the real-number mode used here. Complex mode uses i, where √−1 = i.
Why is my answer a decimal?
Only perfect squares have whole-number square roots. Other roots are often irrational and must be approximated.
Can I calculate a root by hand?
Use the quick square-root method.