Cube Root Calculator
Enter number to find cube root. Cube root = cbrt(Number).
How the result changes
Only number changes; all other inputs stay at your current values. The line illustrates the formula across the shown range. This is not a forecast of real-world outcomes.
About this calculation
Cube Root: find cube root from number. A root reverses a power: the nth root of a value is a number whose nth power gives that value.
Formula
Cube root = cbrt(Number)
Worked example
With Number: 27, cube root is 3.
Calculation method
The rule is Cube root = cbrt(Number).
For this cube root example, changing number from 27 to 28 while keeping the other inputs fixed changes cube root from 3 to 3.036589.
Reading cube root
The principal square root is nonnegative. A cube root can be negative when its input is negative. In the worked values on this page, number 27 produce cube root 3.
Practical use
Use roots to recover a dimension from a squared or cubed quantity or solve a power relationship. The specific task here is to find cube root from number.
Limits and common mistakes
An even root of a negative number is not a real number. For a general nth-root calculation, keep the requested degree and domain clear. Verify number before interpreting cube root; a value measured on another basis would answer a different question.
Why the relationship works
A cube root reverses cubing. It can be negative when the original number is negative, because the cube of a negative number is also negative. Raising the returned value to the third power checks the relationship, allowing for rounded display. The cube root rule uses number in Cube root = cbrt(Number); read each symbol as the field named on this page.
Interpreting another set of values
For cube root, the fields labeled number are the known quantities. The calculator solves for cube root using Cube root = cbrt(Number). The result may be an exact integer, a rounded decimal, an exponent, or a principal root. Preserve the original fraction or expression when a rounded display would lose precision needed later. When comparing two calculations, keep their units and input definitions identical.
For a second cube root check, keep the other default inputs fixed and change number from 27 to 29. Cube root changes from 3 to 3.072317. This is a comparison of two particular cases. Repeat it near the values relevant to your task; do not assume that every formula changes at a constant rate.
Checks and limits
Negative inputs have negative real cube roots, while a zero input returns zero. Rounding the displayed root before cubing it again can produce a small difference from the original number. The reported cube root is 3 in the worked example. Keep its stated unit or counting convention when checking it against another calculation.
Inputs
- Number