Education
Cube Root Calculator
Last updated: May 31, 2026
Written by Blake Boege
A cube root calculator computes the value that, when multiplied by itself twice (cubed), yields the original number. Unlike square roots, real cube roots are defined for all real numbers, including negative values. The calculator rounds decimal results to your preferred precision and checks whether the input is a perfect cube.
Find the cube root ∛x of any positive or negative real number. Includes decimal precision controls and perfect cube validations.
Quick Answer
Calculate the cube root ∛x of any real number. Enter a positive, negative, or decimal value to find the number that, cubed, equals your input.
The number to find the cube root of. Works for positive and negative numbers. · e.g. 27
Cube Root ∛x
3
27 is a perfect cube
27 is a perfect cube. ∛27 = 3 because 3 × 3 × 3 = 27.
Step-by-step solution
Examples
∛27
= 3
∛-8
= -2
∛64
= 4
∛125
= 5
How it works
The Cube Root Operation
The cube root of a number $x$ is written as $\sqrt[3]{x}$ or $x^0.3333333333333333$. It satisfies:
∛x = y where y³ = x
Because any real number has exactly one real cube root, the function is defined across all positive, negative, and zero real inputs.
To compute second-order roots, check our standard square root calculator or use our absolute value calculator for general numerical magnitude checks.
Table of perfect cubes (1 to 10)
| Number (y) | Cube (y³) | Cube Root (∛x) |
|---|---|---|
| 1 | 1 | ∛1 = 1 |
| 2 | 8 | ∛8 = 2 |
| 3 | 27 | ∛27 = 3 |
| 4 | 64 | ∛64 = 4 |
| 5 | 125 | ∛125 = 5 |
| 6 | 216 | ∛216 = 6 |
| 7 | 343 | ∛343 = 7 |
| 8 | 512 | ∛512 = 8 |
| 9 | 729 | ∛729 = 9 |
| 10 | 1000 | ∛1000 = 10 |
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Frequently asked questions
The cube root of a number x is a number y such that y cubed (y × y × y) equals x. For example, the cube root of 27 is 3, because 3 × 3 × 3 = 27.
Yes. Unlike square roots, cube roots are defined for negative numbers in the real number system. This is because multiplying three negative numbers yields a negative result. For example, ∛−8 is −2 because (−2) × (−2) × (−2) = −8.
A square root asks what number multiplied by *itself* once equals the value: √9 = 3 (since 3 × 3 = 9). A cube root asks what number multiplied by itself *twice* equals the value: ∛27 = 3 (since 3 × 3 × 3 = 27). Additionally, square roots of negative numbers require imaginary numbers, while negative cube roots are real numbers.
A perfect cube is an integer whose cube root is also an integer. Examples include 1, 8, 27, 64, 125, 216, 343, 512, 729, and 1000.
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