Square Root Calculator

Calculate the square root, cube root, or any nth root of a number. Includes a perfect squares reference table.

Calculate Root

2

Perfect Squares Reference (1–20)

11
24
39
416
525
636
749
864
981
10100
11121
12144
13169
14196
15225
16256
17289
18324
19361
20400

How to Use This Tool

  1. Choose a root using the preset buttons (√ Square, ∛ Cube, ⁴√ 4th) or type any root value n into the "Root (n)" field.
  2. Enter the number x you want to find the root of in the "Number (x)" field.
  3. Read the result — the calculator instantly computes the nth root as you type.
  4. Check the verification line, which shows the result raised back to the power n to confirm it equals x.
  5. Look for the "Perfect Square/Cube/Power" badge, which appears when the result is a whole number.
  6. Use the Perfect Squares Reference table below to quickly look up squares of 1 through 20.

Formula & How It Works

Square Root

√x = x^(1/2)

The value that, when multiplied by itself, equals x.

Cube Root

∛x = x^(1/3)

The value that, when cubed (multiplied by itself three times), equals x.

nth Root

ⁿ√x = x^(1/n)

The value that, when raised to the power n, equals x. This calculator computes it as x raised to the power 1/n.

Negative Base Rule

ⁿ√(−x) is real only when n is odd

Even-order roots of negative numbers are not real; odd-order roots of negative numbers return a negative real result.

Practical Examples & Common Use Cases

Example: Square Root of 144

√144 = 144^(1/2) = 12, because 12 × 12 = 144.

Example: Cube Root of 27

∛27 = 27^(1/3) = 3, because 3 × 3 × 3 = 27.

Example: 4th Root of 81

⁴√81 = 81^(1/4) = 3, because 3 × 3 × 3 × 3 = 81.

Frequently Asked Questions

The square root of a number x is the value that, when multiplied by itself, gives x. For example, √49 = 7 because 7 × 7 = 49.

The nth root of x is x raised to the power of 1/n. For example, the 4th root of 81 = 81^(1/4) = 3.

Not in real numbers. The square root of a negative number is an imaginary number (e.g. √−1 = i). However, odd roots of negative numbers are real — for example, ∛−8 = −2.

A perfect square is an integer whose square root is also an integer. Examples: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100.

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