Root Calculator
Roots undo powers
Roots reverse exponentiation: the nth root of x is the number that, multiplied by itself n times, gives x. The cube root of 27 is 3 because 3 × 3 × 3 = 27. Every positive number has exactly one positive nth root for any n, which calculators report by default; for example, 16 also has a negative 4th root, −2, since (−2)⁴ = 16 too. Negative radicands behave differently by parity — odd roots stay real (−2 cubed is −8, so ∛−8 = −2), while even roots of negatives have no real value and need complex numbers.
Frequently Asked Questions
Why does the calculator only show the positive square root?
The radical sign conventionally means the principal (non-negative) root. Keep in mind both +3 and −3 square to 9 when you are solving equations like x² = 9 — the answer there is x = ±3.
How do I take a root with this calculator?
Enter the number as the radicand and the root as the index: 2 for square root, 3 for cube root, 5 for fifth root, any whole number up to 100. The check row raises the result back to confirm it.