Find the square root, cube root or any nth root of a number, with the exact value where one exists.
How this calculator arrives at its answer
A square root asks what number multiplied by itself gives your input. The same idea generalises to any index — a cube root asks for three equal factors, and so on.
Perfect squares and perfect cubes come out as whole numbers; everything else is irrational and shown to several decimal places.
Step by step
- Enter the number.
- Choose the root index — 2 for square root, 3 for cube root.
- Read the result.
Formula reference
ⁿ√x = x^(1/n)
perfect square: a whole number whose root is also whole
A worked example
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.
Questions people ask about this
Can you take the square root of a negative number?
Not within the real numbers. The result is imaginary, written as a multiple of i.
What is a perfect square?
A number whose square root is a whole number — 1, 4, 9, 16, 25 and so on.