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Square Root Calculator

Calculate square root, cube root, or any nth root with decimal precision

Results are estimates for informational purposes only — not professional financial, medical, or legal advice. See how we build and verify our calculators.

Frequently Asked Questions

What is a square root?

The square root of a number x is a value y such that y² = x. For example, √144 = 12 because 12² = 144. Every positive number has two square roots (positive and negative), but we conventionally report the positive (principal) root.

What is an irrational square root?

Most square roots are irrational — they cannot be expressed as a simple fraction and their decimals go on forever without repeating. √2 = 1.41421356... Perfect squares (1, 4, 9, 16, 25...) have exact integer square roots.

What are perfect squares?

Numbers whose square roots are whole integers: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400... The square root of a perfect square is always an integer.

How do I simplify a square root?

Factor out perfect squares. Example: √72 = √(36×2) = 6√2. Find the largest perfect square factor, take its root, and leave the remainder under the radical.

What is the difference between square root and exponent 0.5?

They are identical. √x = x^(1/2) = x^0.5. Similarly, cube root = x^(1/3). This is why calculators use the ^ operator for roots as well as powers.

Common Square Roots

NumberSquare RootExact?
21.41421No
31.73205No
52.23607No
72.64575No
103.16228No
123.46410No
255Yes
507.07107No

Simplifying Square Roots

Factor out perfect squares to simplify:

√12=√(4×3) = 2√3 ≈ 3.464
√18=√(9×2) = 3√2 ≈ 4.243
√50=√(25×2) = 5√2 ≈ 7.071
√72=√(36×2) = 6√2 ≈ 8.485
√98=√(49×2) = 7√2 ≈ 9.899