How do I use the root calculator?

Enter the radicand (the number under the root) and the index (the degree of the root, e.g., 2 for square root, 3 for cube root). The calculator will compute the nth root instantly.

What is the index in a root calculation?

The index is the small number that indicates the degree of the root. For example, in the square root, the index is 2; in the cube root, it is 3. If no index is given, it is usually 2.

Can I calculate the square root with this calculator?

Yes, simply set the index to 2 and enter the radicand. The calculator will return the square root.

Math

Instant, private, and free

Root Calculator.

Calculate a real nth root, including odd roots of negative values.

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Set your values

Results update as you type.

02 / ANSWER

Radicand

Index

Radicand must be finite.

Results update automatically as you type.

Use Cases

Solve math homework problems

Quickly verify answers for root calculations in algebra or geometry assignments.

Example: Check the cube root of 27 (index 3, radicand 27) equals 3.

Engineering and science calculations

Compute roots for formulas involving volumes, areas, or physical constants.

Example: Find the fourth root of 81 for a formula.

Frequently Asked Questions

How do I use the root calculator?: Enter the radicand (the number under the root) and the index (the degree of the root, e.g., 2 for square root, 3 for cube root). The calculator will compute the nth root instantly.
What is the index in a root calculation?: The index is the small number that indicates the degree of the root. For example, in the square root, the index is 2; in the cube root, it is 3. If no index is given, it is usually 2.
Can I calculate the square root with this calculator?: Yes, simply set the index to 2 and enter the radicand. The calculator will return the square root.

Tips & Common Mistakes

Tips

For square roots, set the index to 2. For cube roots, set it to 3.
If the radicand is negative and the index is even, the result is not a real number. The calculator may show an error or a complex result.
Use the calculator to check your manual calculations or to save time on repetitive root computations.
Remember that the nth root of a number is the value that, when raised to the power of n, gives the original number.

Common Mistakes to Avoid

Confusing the radicand and the index: the radicand is the number under the root, the index is the degree.
Forgetting that the square root has an index of 2, not 1.
Assuming that the root of a negative number is always invalid; it is valid for odd indices.

Last updated: August 13, 2026