Math

Nth Root Calculator

Find a real nth root, allowing negative radicands only for odd integer roots.

Exact method explained belowEditable inputs
Calculation notebook
Calculation notebook

The formula and worked example below explain the calculation.

See the method

Enter your values

Runs on your device

Your answer

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter radicand, root degree.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

The real nth root of nonnegative x is x^(1/n). For negative x and odd n, take −(|x|^(1/n)); even roots of negative values have no real result.

A WORKED EXAMPLE

Using radicand = -125, root degree = 3, the result is -5. Change these example inputs to match your task; use the method above to check each step.

Understanding your result

The radical notation uses the principal nonnegative root for a nonnegative input. Solving x⁴ = a as an equation is a different task and can have two real roots.

What to keep in mind

Returns the real root only, not all complex roots. Non-integer root degrees are unsupported. Finite-precision arithmetic is used. Check the domain and the stated convention before using an approximation.

Common questions

Does a fourth root return both signs?

The radical notation uses the principal nonnegative root for a nonnegative input. Solving x⁴ = a as an equation is a different task and can have two real roots.

How can I check the result?

The real nth root of nonnegative x is x^(1/n). For negative x and odd n, take −(|x|^(1/n)); even roots of negative values have no real result. The worked example uses editable inputs. Calculations run on your device; no external API or account is required.

Methodology maintained by ClarityKit. How these tools are built and checked.