Quick start
- Enter the radicand, which is the number inside the root.
- Enter the root index, such as 2 for square root or 3 for cube root.
- Press Calculate root.
- Review the answer, exponent form, power check, and steps.
- Use examples, recent answers, or Copy answer while checking root problems.
What roots mean
A root asks what number can be raised to a power to return the radicand. For example, root_2(144) equals 12 because 12^2 equals 144.
A cube root asks for a number that returns the radicand when cubed. root_3(125) equals 5 because 5^3 equals 125.
Exponent form
Roots can be rewritten as rational exponents. The nth root of x is the same as x^(1/n). That is why root_4(81) can also be written as 81^(1/4).
Negative radicands
Odd roots of negative numbers can have real-number answers. For example, root_3(-125) equals -5 because -5 cubed equals -125.
Even roots of negative numbers are not real numbers. The calculator will show an error for cases such as root_2(-16).
Examples from the root calculator
12
-5
3
Common mistakes
Use a whole-number root index. Index 2 means square root, index 3 means cube root, and larger whole numbers are nth roots.
Check whether the answer is exact or rounded. Some roots, such as root_2(2), are irrational and will appear as a decimal approximation.
History, privacy, and copying
Recent root answers stay visible in the page while you work. The history is kept only in the current browser tab and is not sent to a server.
Copy answer copies the root expression and result so you can paste it into notes, homework, a message, or another document.