Find the square root, cube root or any n-th root of a number.
What this calculator does
Enter a number and a root index and this calculator returns the n-th root, plus the square and cube roots for convenience.
A root is the inverse of a power — the n-th root undoes raising to the n-th power.
Step by step
- Enter the number.
- Enter the root index (2 for square root, 3 for cube root).
- Read the result.
The formula
n-th root of x = x^(1 ÷ n)
The default scenario, worked through
On the values this calculator opens with, the n-th root is 3. Underneath, Square root comes out at 5.19615 and Cube root at 3. Change any field and every figure updates as you type.
Frequently asked questions
How do I find an n-th root?
Raise the number to the power of one over n. The cube root of 27 is 27^(1/3) = 3.
Can I take the root of a negative number?
Odd roots of negatives are real (the cube root of −8 is −2); even roots of negatives aren’t real numbers.
Is a root the same as a fractional exponent?
Yes — x^(1/n) is exactly the n-th root of x.