Exponent and Root Calculator (Power, Square Root, Cube Root, n-th Root)
Raise a number to any power (including fractional and negative exponents) and take its square root, cube root and n-th root.
Things to keep in mind:
- Complex results (e.g. √−4 = 2i) are not computed; 0 and "real = 0" are shown instead.
- Very small results (e.g. 10⁻²⁰) are rounded to 8 decimals and may show as 0.00000000.
- Base ±1,000,000, exponent ±1,000, radicand ±10¹² and root index 1–100.
Calculator
Result
Enter the values and press Calculate to see the result here.
About this tool
The tool has two parts: powers (xʸ) and roots (ⁿ√a). Powers work with whole, fractional and negative exponents; the root part returns the square root, the cube root and the n-th root you choose for the same number.
Rules and formulas
- xʸ: for a whole y, x multiplied by itself y times; x⁰ = 1, x⁻ʸ = 1 / xʸ
- A fractional exponent is a root: x^(1/n) = ⁿ√x, x^(m/n) = (ⁿ√x)ᵐ
- ⁿ√a = a^(1/n); √a = a^(1/2), ∛a = a^(1/3)
- A negative a has a real root only for an odd whole n: ⁿ√a = −ⁿ√|a| (e.g. the fifth root of −32 is −2)
- A negative base is raised only to whole exponents: (−2)³ = −8, but (−8)^0.5 is not a real number
Example: 2¹⁰ = 1024; the cube root of 27 is 3 and its square root √27 ≈ 5.19615242. 1.5⁻² = 1 / 2.25 ≈ 0.44444444.
Undefined cases (a negative base with a fractional exponent, zero to a negative power, an even root of a negative number) are reported as 0 with the "computed = 0" flag instead of an error. Powers above roughly 10²⁹ are not computed either.
Extra example: 1000^0.4 ≈ 15.84893192. The fifth root of −32 is −2; the cube root of the same number is ≈ −3.17480210, while its square root is not real and shows 0.
How to read the result: check the “Power computed” and “n-th root is real” flags first: 1 means the result is valid, 0 means it is undefined or not a real number and the related value is shown as 0. Results are rounded to 8 decimals; irrational values (such as √27) are approximations. The cube root is always real for negative numbers; the square root and other even roots are computed only for non-negative numbers.
How to use
- In the power part enter the base (x) and the exponent (y).
- In the root part enter the radicand (a) and the root index (n).
- Press Calculate; the power, n-th root, square root and cube root are shown together.
Notes
Arithmetic uses 64 significant digits and results are rounded to 8 decimals (HALF_UP), so irrational results such as √2 are approximations. 0⁰ is taken as 1. A power is not computed when |y × ln|x|| exceeds 66.775 (about 10²⁹). The n-th root of a negative number is returned as −ⁿ√|a| only when n is an odd whole number (3, 5, 7 …); the cube root of a negative number is always real.
Frequently asked questions
It is the power of the reciprocal: x⁻ʸ = 1 / xʸ. For example 2⁻³ = 1/8 = 0.125 and 1.5⁻² ≈ 0.44444444.
A fractional exponent is a root: x^0.5 = √x, x^(1/3) = ∛x. For example 2^0.5 ≈ 1.41421356 and 1000^0.4 ≈ 15.84893192.
In the real numbers only odd roots exist: ∛−8 = −2, the fifth root of −32 is −2. Even roots such as the square root are not real for negative numbers; the tool shows 0.
When the result is not real (negative base, fractional exponent), undefined (zero to a negative power) or larger than about 10²⁹, the tool returns 0 and the flag 0 instead of an error.
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