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Exponent Calculator

Raise any number to any power, including negative and fractional exponents, or solve for the base or the exponent itself.

What do you want to work out?

About the Exponent Calculator

An exponent is shorthand for repeated multiplication. Writing 2¹⁰ instead of 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 saves space, but the real gain is that the notation turns out to mean something sensible far beyond whole numbers.

A negative exponent means a reciprocal. A fractional exponent means a root. A zero exponent means one. None of these were decided by committee — each follows from the pattern the whole numbers already establish, and the section below shows how.

This calculator raises a number to any power, and also works backwards: given a result, it can find the base or the exponent that produced it.

How to Use the Exponent Calculator

Three modes.

Raise a number to a power takes a base and an exponent. Both can be negative or fractional, within the limits described below.

Find the base takes a result and an exponent, and works out what number was raised. This is a root: if b⁵ = 32, then b is the fifth root of 32.

Find the exponent takes a base and a result, and works out the power. This is a logarithm, and the working shows it being used.

Every mode returns the answer, the repeated multiplication written out where the exponent is small enough for that to be readable, and the value in scientific notation — useful because powers grow very large very quickly.

How Exponents Are Calculated

For a whole positive exponent, you multiply the base by itself that many times. 2⁵ is 2 × 2 × 2 × 2 × 2 = 32. That is the definition, and everything else extends it.

Zero. Look at what happens going down the powers of 2:

2^4 = 16
2^3 = 8     (16 / 2)
2^2 = 4     ( 8 / 2)
2^1 = 2     ( 4 / 2)
2^0 = 1     ( 2 / 2)

Each step divides by the base. Continuing the pattern to zero gives 1, and it gives 1 for every base. The rule is not an arbitrary convention — it is the only value that keeps the pattern consistent.

Negative exponents. Keep going down:

2^-1 = 1/2   (1 / 2)
2^-2 = 1/4
2^-3 = 1/8

A negative exponent means the reciprocal of the positive power. Note what it does not mean: the result is never negative. 2⁻³ is 0.125, not −8.

Exponent Formula

b^n   = b x b x ... x b     (n times)
b^0   = 1                   (for any b other than 0)
b^-n  = 1 / b^n
b^(1/n) = the nth root of b
b^(m/n) = the nth root of b, raised to the power m

The laws that make exponents worth using:

b^m x b^n = b^(m+n)        multiplying adds exponents
b^m / b^n = b^(m-n)        dividing subtracts them
(b^m)^n   = b^(m x n)      a power of a power multiplies them
(a x b)^n = a^n x b^n      a power distributes over multiplication

Solving backwards uses the inverse operations. To find the base, take a root. To find the exponent, take a logarithm:

b = result^(1/n)
n = log(result) / log(b)

Step-by-Step Example

Calculate 2¹⁰.

Step 1 — recognise it as repeated multiplication. Ten twos multiplied together.

Step 2 — build it up by doubling. 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024.

The answer is 1024, which is why a kilobyte is 1024 bytes rather than 1000: computing counts in powers of two.

Now a negative exponent. What is 2⁻³?

Step 1: the negative means a reciprocal   ->  1 / 2^3
Step 2: 2^3 = 8
Step 3: 1 / 8 = 0.125

Positive, less than one, and nowhere near −8.

And a fractional one. What is 8^(2/3)?

Step 1: the denominator is the root       ->  cube root of 8 = 2
Step 2: the numerator is the power        ->  2^2 = 4

The answer is 4. Taking the root first keeps the numbers small — doing it the other way round means cube-rooting 64, which is the same answer by a harder path.

Understanding Your Result

The answer is the value itself.

Written out shows the repeated multiplication when the exponent is a small whole number, which makes the operation concrete. For a negative exponent it shows the reciprocal form, so you can see why the result is a fraction.

Scientific notation matters here more than almost anywhere else, because exponents produce enormous numbers from small inputs. 2¹⁰⁰ has 31 digits; the scientific form is readable and the plain form is not.

Two sanity checks worth running. A base greater than 1 with a positive exponent gives a result larger than the base — always. A base between 0 and 1 with a positive exponent gives a result smaller than the base, because multiplying by a fraction shrinks things. 0.5³ is 0.125.

When Should You Use This Calculator?

Compound growth. Interest, population, anything multiplying by a fixed factor each period is a power. The balance after n years is the principal times (1 + rate)ⁿ.

Computing. Storage sizes, address spaces and algorithmic complexity are all powers of two. 2³² is why 32-bit systems stopped at about 4 billion.

Science. Orders of magnitude, decay, intensity that falls with the square of distance.

Geometry. Area scales with the square of a length and volume with the cube. Doubling a cube's side gives eight times the volume, not two.

Algebra homework. Checking work with negative and fractional exponents, where the rules are easy to misapply.

Working backwards. "How many years until this doubles?" is solving for an exponent, which is what the third mode does.

Common Mistakes

Thinking a negative exponent gives a negative result. 2⁻³ is 0.125. The minus sign flips the number into a reciprocal, not across zero.

Multiplying the base by the exponent. 2¹⁰ is 1024, not 20. This sounds too obvious to happen and it happens constantly under time pressure.

Adding exponents when the bases differ. 2³ × 3³ is not 6⁶ or 5³. The rule b^m × b^n = b^(m+n) requires the same base. With different bases and the same exponent you can combine the other way: 2³ × 3³ = 6³.

Confusing (b^m)^n with b^(m^n). The first multiplies the exponents, giving b^(mn). The second is a tower and is vastly larger. (2³)² is 64; 2^(3²) is 512.

Taking an even root of a negative number. (−4)^½ has no real answer. Odd powers are fine — (−8)^(1/3) is −2 — because an odd number of negative factors stays negative.

Forgetting that 0⁰ is contested. Most contexts define it as 1 for convenience, but it is a special case rather than a straightforward consequence of the rules.

Expecting a fractional base to grow. 0.9¹⁰ is about 0.35. Repeatedly multiplying by something less than one shrinks toward zero, which is why a 10% annual decline compounds to far more than 100% over a decade — it never quite reaches nothing.

Frequently Asked Questions

Why does any number to the power of zero equal one?

Because dividing a power by the base reduces the exponent by one. Two cubed is eight, two squared is four, two to the first is two, and continuing the pattern by halving gives two to the zero as one. The rule follows from the pattern rather than being imposed on it.

What does a negative exponent mean?

It means the reciprocal of the positive power. Two to the negative three is one over two cubed, which is one eighth. A negative exponent never makes the result negative; it makes it a fraction between zero and one, assuming the base is positive.

What does a fractional exponent mean?

It is a root. A power of one half is the square root, one third is the cube root, and two thirds means the cube root squared. This is consistent with the multiplication rule, since a half plus a half is one, and a square root multiplied by itself gives the original number.

Why can a negative base not take a fractional exponent?

Because it would ask for an even root of a negative number, which has no real answer. The square root of negative four does not exist among real numbers, so negative four to the power of one half is undefined unless you work with complex numbers.

How do exponents combine?

Multiplying powers of the same base adds the exponents, dividing subtracts them, and raising a power to another power multiplies them. Two cubed times two to the fourth is two to the seventh, because you are multiplying by two three times and then four more times.

Last reviewed September 17, 2026 by the CalculatorPeak editorial team.