What an nth root is
The nth root of a number x is a value that, when multiplied by itself n times, gives back x. The square root (n=2) and cube root (n=3) are the most common cases, but this calculator works for any positive whole-number degree.
The formula
The nth root is calculated as x1/n. For even roots (like square roots), negative radicands have no real result, so the calculator returns 0 in that case. For odd roots (like cube roots), negative numbers do have a real root — for example, the cube root of -27 is -3 — and the calculator handles this using −(−x)1/n.
The “check” value multiplies the result by itself n times so you can verify it returns close to your original number. This tool is for general math and educational purposes.
Last reviewed August 2026