Square root
root_2(144)12 because 12^2 = 144
Use this free root calculator to find square roots, cube roots, and nth roots with real-number guardrails, exponent form, power checks, decimal examples, and steps.

Recent root answers will appear here.
Use index 2 for square roots and index 3 for cube roots.
Negative radicands need an odd whole-number root index for real-number answers.
Find square roots and cube roots for math, science, and study problems.
Calculate nth roots such as fourth roots, fifth roots, and higher whole-number roots.
Convert root notation into rational exponent form.
Check whether a negative radicand has a real-number root.
Check decimal roots such as the cube root of 0.008.
Raise the answer back to the root index to verify the power check.
12 because 12^2 = 144
-5 because (-5)^3 = -125
3 because 3^4 = 81
2 because 2^5 = 32
0.2 because 0.2^3 = 0.008
No real-number result
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Quick answers about square roots, cube roots, nth roots, negative radicands, exponent form, and privacy.
An nth root asks what number raised to the nth power gives the radicand. For example, the cube root of 125 is 5 because 5^3 = 125.
A square root uses index 2, so the answer squared returns the radicand. A cube root uses index 3, so the answer cubed returns the radicand.
The main inputs are the numbers, operation, mode, or known values the calculator needs. Keep units consistent, enter percentages the way the page label shows, and use the examples as a quick check before trusting the answer.
Read the headline answer, then check the supporting lines and examples to understand how the calculator got there. If one input changes, rerun the tool and compare the new answer instead of guessing.
Check units, signs, rounding, and the selected mode before copying the answer. If the number feels weird, rerun one of the examples first, then put your own values back in slowly.
The radicand is the number inside the root. The root index tells which power to undo: index 2 is square root, index 3 is cube root, index 4 is fourth root, and so on.
It can calculate real odd roots of negative numbers, such as root_3(-125) = -5. Even roots of negative numbers are not real numbers, so the calculator shows an error.
In real numbers, an even power is never negative. That is why root_2(-16) and root_4(-81) do not have real-number answers on this page.
A root can be rewritten as a rational exponent. The nth root of x is the same as x^(1/n).
Raise the answer to the root index. If root_5(32) returns 2, check it by calculating 2^5, which gives 32.
Some roots do not land on a whole number. For example, root_2(2) is about 1.41421356, so the calculator gives a decimal approximation.
No. This calculator uses positive whole-number root indexes of 2 or higher, such as 2, 3, 4, or 5.
Yes. Decimal radicands work when the root has a real-number answer. The cube root of 0.008 is 0.2 because 0.2^3 = 0.008.
Yes. Recent root answers stay only in the current browser tab while you use the page. They are not sent to a server.