Square Root Calculator
Calculate the square root, cube root, or any nth root of a number. Includes a perfect squares reference table.
Calculate Root
Perfect Squares Reference (1–20)
How to Use This Tool
- Choose a root using the preset buttons (√ Square, ∛ Cube, ⁴√ 4th) or type any root value n into the "Root (n)" field.
- Enter the number x you want to find the root of in the "Number (x)" field.
- Read the result — the calculator instantly computes the nth root as you type.
- Check the verification line, which shows the result raised back to the power n to confirm it equals x.
- Look for the "Perfect Square/Cube/Power" badge, which appears when the result is a whole number.
- 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 oddEven-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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