acalculator

What is a number to an exponent?

Calculate exponents and powers. Raise numbers to any power with our calculator.

Your numbers

Result
8

2 to the power of 3 is 8.

Result: 8. 2 to the power of 3 is 8.

Result by exponent

How to calculate

Raises a base to an exponent, or finds the exponent or the base from the other two numbers.

Example with the default inputs (Base 2, Exponent 3): 2 to the power of 3 is 8.

Formula: r = bⁿ: the result r is the base b raised to the exponent n.

  • Real numbers only: a negative base needs a whole-number exponent.
  • 0⁰ and 0 raised to a negative power are undefined, so they have no answer.
  • Solving for the base with an even whole exponent gives two answers, a positive and a negative one.

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Base 2, Exponent 3 gives Result 8.Source: OpenStax, Elementary Algebra 2e, §6.2 Use Multiplication Properties of Exponents. https://openstax.org/books/elementary-algebra-2e/pages/6-2-use-multiplication-properties-of-exponents
  2. Base 10, Exponent -2 gives Result 0.01.Source: OpenStax, Elementary Algebra 2e, §6.2 Use Multiplication Properties of Exponents. https://openstax.org/books/elementary-algebra-2e/pages/6-2-use-multiplication-properties-of-exponents
  3. Base -2, Exponent 3 gives Result -8.Source: OpenStax, Elementary Algebra 2e, §6.2 Use Multiplication Properties of Exponents. https://openstax.org/books/elementary-algebra-2e/pages/6-2-use-multiplication-properties-of-exponents
  4. Base 2, Result 1,024 gives Exponent 10.Source: OpenStax, Elementary Algebra 2e, §6.2 Use Multiplication Properties of Exponents. https://openstax.org/books/elementary-algebra-2e/pages/6-2-use-multiplication-properties-of-exponents
  5. Exponent 2, Result 81 gives Base 9.Source: OpenStax, Elementary Algebra 2e, §6.2 Use Multiplication Properties of Exponents. https://openstax.org/books/elementary-algebra-2e/pages/6-2-use-multiplication-properties-of-exponents
  6. Base 2.5, Exponent 2.5 gives Result 9.882118.Source: OpenStax, Elementary Algebra 2e, §6.2 Use Multiplication Properties of Exponents. https://openstax.org/books/elementary-algebra-2e/pages/6-2-use-multiplication-properties-of-exponents

How it works

The calculator solves one equation for whichever number you leave empty:

r = bⁿ

where b is the base, n is the exponent and r is the result. Fill in any two and it finds the third.

  • Result: r = bⁿ. For a whole n this is b multiplied by itself n times; for a negative n it is 1 ÷ b⁻ⁿ; for a decimal n it is e^(n × ln b).
  • Exponent: n = ln r ÷ ln b (the logarithm of r in base b). For a negative base, only a whole exponent gives a real result, so n must be a whole number and bⁿ must have the same sign as r.
  • Base: b = r^(1/n). With an odd whole exponent there is one real base, with the same sign as r. With an even whole exponent and r > 0 there are two, +r^(1/n) and −r^(1/n), and the calculator shows both. With any other exponent the base must be positive.

Assumptions

  • Real numbers only. A negative base with a decimal exponent, such as (−8)^0.5, is not a real number, so there is no answer.
  • 1ⁿ = 1, (−1)ⁿ = ±1 and 0ⁿ = 0 hold for many exponents, so solving for the exponent from base 0, 1 or −1 has no single answer.
  • An exponent or a base within float error of a whole number is shown as that whole number (log 1,000 ÷ log 10 is 3).
  • 0⁰ gives no answer, and the page says it has no single value (it is often taken as 1). 0 to a negative power gives no answer because it divides by 0. A result past double range (about 1.8 × 10³⁰⁸, or closer to 0 than about 2.2 × 10⁻³⁰⁸) gives no numeric answer; the page says it is too large (or too small) to show exactly and gives it as a power of ten to 6 significant figures, from log₁₀ |r| = n × log₁₀ |b|, with a minus sign for a negative base and an odd exponent: 10⁴⁰⁰ is "about 1 × 10^400".

Worked examples by hand

2³. 2 × 2 × 2 = 8.

10⁻². 1 ÷ 10² = 1 ÷ 100 = 0.01.

(−2)³. (−2) × (−2) × (−2) = 4 × (−2) = −8.

2 to what power is 1,024? 2¹⁰ = 1,024, so n = log₂ 1,024 = 10.

What number squared is 81? 9² = 81 and (−9)² = 81, so the base is 9 or −9.

2.5^2.5. 2.5^2.5 = 2.5² × √2.5 = 6.25 × 1.5811388… = 9.8821177…

Other questions people ask

What is exponentiation and how does it work?

Exponentiation is a mathematical operation that raises a base number to a given power (exponent). It's written as a^b where 'a' is the base and 'b' is the exponent. For example, 2^3 = 2 × 2 × 2 = 8. The exponent tells you how many times to multiply the base by itself. Exponentiation is fundamental in mathematics, science, and engineering for modeling growth, decay, and complex calculations.

What are the most common types of exponents?

Common exponent types include: 1) Positive integers (2^3 = 8) - repeated multiplication; 2) Zero (x^0 = 1) - any number to power 0 equals 1; 3) Negative integers (2^-3 = 1/8) - reciprocal of positive power; 4) Fractions (8^(1/3) = 2) - roots; 5) Decimals (2^1.5 ≈ 2.83) - decimal powers, which are roots of powers (2^1.5 = √(2³)). Each type has specific mathematical properties and applications in different fields.

How do I calculate negative exponents?

Negative exponents represent reciprocals. The formula is a^(-b) = 1/(a^b). For example, 2^(-3) = 1/(2^3) = 1/8 = 0.125. This works for any non-zero base. Negative exponents are useful in scientific notation, probability calculations, and when working with very small numbers. They're also essential in calculus and advanced mathematics.

What are the key properties of exponents?

Key exponential properties include: 1) a^0 = 1 (any number to power 0 equals 1); 2) a^1 = a (any number to power 1 equals itself); 3) a^m × a^n = a^(m+n) (product rule); 4) a^m ÷ a^n = a^(m-n) (quotient rule); 5) (a^m)^n = a^(m×n) (power rule); 6) (a×b)^n = a^n × b^n (distributive rule). These properties make exponentiation powerful for simplifying complex expressions.

Why is 0^0 undefined?

0^0 leads to contradictory results depending on how you approach it. If you consider it as lim(x→0) x^0, you get 1. But if you consider it as lim(x→0) 0^x, you get 0. Since these limits don't agree, 0^0 is an indeterminate form in analysis. Some fields (algebra, combinatorics) define 0^0 = 1 by convention; this calculator follows the analysis view and shows no answer for 0^0. This is different from other cases like 0^1 = 0 or 1^0 = 1, which are well-defined.

What is the relationship between exponents and logarithms?

Exponents and logarithms are inverse operations. If y = a^x, then x = log_a(y). This means they 'undo' each other: log_a(a^x) = x and a^(log_a(x)) = x. For example, if 2^3 = 8, then log_2(8) = 3. This inverse relationship is fundamental in solving exponential equations and modeling growth/decay processes in science and finance.

How are exponents used in real-world applications?

Exponents have numerous real-world applications: 1) Compound interest and financial growth (A = P(1+r)^t); 2) Population growth modeling; 3) Radioactive decay in physics; 4) Sound intensity and decibel calculations; 5) pH scale in chemistry; 6) Algorithm complexity in computer science; 7) Earthquake magnitude scales. They're essential for understanding phenomena that grow or decay exponentially.

What's the difference between exponential growth and linear growth?

Linear growth increases by a constant amount (y = mx + b), while exponential growth increases by a constant factor (y = a^x). For example, $100 growing at 10% annually is exponential: $100, $110, $121, $133.10... Each year multiplies by 1.1. Linear growth would be $100, $110, $120, $130... adding $10 each year. Exponential growth eventually outpaces linear growth dramatically.

How do I solve exponential equations?

To solve exponential equations: 1) Use logarithms to bring exponents down: if a^x = b, then x = log_a(b); 2) Apply exponential properties to combine or separate terms; 3) Use the inverse relationship between exponents and logarithms; 4) Check for extraneous solutions. For example, to solve 2^x = 8, take log_2 of both sides: x = log_2(8) = 3.

What are fractional exponents and how do they work?

Fractional exponents represent roots. The formula is a^(m/n) = (nth root of a)^m. For example, 8^(1/3) = cube root of 8 = 2, and 4^(3/2) = (square root of 4)^3 = 2^3 = 8. Fractional exponents allow us to express roots using exponential notation, making calculations more consistent and enabling the use of exponential properties with roots.

How do exponents relate to scientific notation?

Scientific notation uses powers of 10 to express very large or small numbers. For example, 6.02 × 10^23 represents 602 followed by 21 zeros. The exponent tells you how many places to move the decimal point. Positive exponents move right (larger numbers), negative exponents move left (smaller numbers). This notation is essential in physics, chemistry, and astronomy for handling numbers spanning many orders of magnitude.

What are the historical origins of exponential notation?

Exponential notation was developed by René Descartes in the 17th century, though the concept of repeated multiplication dates back to ancient civilizations. Descartes introduced the modern superscript notation (a^b) in his work 'La Géométrie' (1637). This notation revolutionized mathematics by providing a compact way to express repeated multiplication and enabling the development of calculus and modern mathematical analysis.