Power Calculator
What an exponent means
xⁿ means x multiplied by itself n times: 2⁵ = 2 × 2 × 2 × 2 × 2 = 32. The calculator also handles exponents that are negative, decimal or fractional.
The rules of exponents
| Rule | Example |
|---|---|
| xᵃ × xᵇ = xᵃ⁺ᵇ | 2³ × 2⁴ = 2⁷ = 128 |
| xᵃ ÷ xᵇ = xᵃ⁻ᵇ | 10⁵ ÷ 10² = 10³ = 1,000 |
| (xᵃ)ᵇ = xᵃˣᵇ | (3²)³ = 3⁶ = 729 |
| x⁰ = 1 | 7⁰ = 1 |
| x⁻ⁿ = 1 ÷ xⁿ | 10⁻³ = 0.001 |
| x^(1/n) = ⁿ√x | 2^0.5 = √2 ≈ 1.414 |
Worked examples
- 2¹⁰ = 1,024 — why a kilobyte was historically 1,024 bytes.
- 10⁻³ = 0.001 — the prefix "milli".
- 27^(1/3) = 3, the cube root of 27.
- 1.05¹⁰ = 1.629: money growing 5% a year for 10 years is multiplied by about 1.63.
Powers and growth
Exponents describe anything that grows by a fixed percentage: savings with compound interest, inflation, population or the spread of an epidemic. A value multiplied by 2 every period grows to 2¹⁰ = 1,024 times its size after 10 periods and over a million times after 20. This "exponential growth" is why small differences in a rate matter so much over long periods.
Scientific notation
Very large or small numbers are written as a number between 1 and 10 times a power of 10: the speed of light is about 3 × 10⁸ m/s; a red blood cell is about 8 × 10⁻⁶ m wide. Multiplying such numbers means multiplying the first parts and adding the exponents.
Special cases
- A negative base with a fractional exponent (for example (−8)^0.5) has no real result; the calculator shows an error.
- 0⁰ is conventionally taken as 1 in most contexts.
- Very large results may be shown rounded; for precise work with huge numbers, use scientific software.
Frequently Asked Questions
What does a negative exponent mean?
It means the reciprocal: x⁻ⁿ = 1 ÷ xⁿ. For example, 2⁻³ = 1 ÷ 8 = 0.125.
How do I calculate a root with this tool?
Use a fractional exponent: the square root is ^0.5, the cube root ^(1/3) ≈ 0.3333, the fourth root ^0.25.
Why is any number to the power 0 equal to 1?
Because xᵃ ÷ xᵃ = xᵃ⁻ᵃ = x⁰, and any non-zero number divided by itself equals 1.