Square root calculator

This tool calculates the square root (racine carrée) of any number, and can also find higher roots such as cube roots and fourth roots. For whole numbers it gives the simplified radical form too — for example, it shows that √72 = 6√2 — which is exactly how answers are expected in algebra and exams.

What is a square root?

The square root of a number x is the value that, when multiplied by itself, gives x. For example, √25 = 5 because 5 × 5 = 25. A perfect square (like 25, 36, or 49) has a whole-number root, while most numbers have an irrational root that goes on forever — so we either round it or leave it in simplified radical form.

Simplifying radicals

To simplify a square root, pull out the largest perfect-square factor. For √72, the factor 36 comes out as 6, leaving √2, so √72 = 6√2. This calculator does that automatically for whole numbers. For other calculations, see the scientific calculator.

Frequently asked questions

Can you take the square root of a negative number?

Not within the real numbers — the result would be imaginary. Odd roots (like cube roots) of negative numbers are real, however; for example, the cube root of −8 is −2.

How do I find a cube root here?

Set the root field to 3. You can use any value of 2 or higher for the root.