Reciprocals turn division into multiplication and appear in rates (seconds per metre versus metres per second), lens equations, parallel resistors and unit conversions.
How to use the Reciprocal Calculator
- Type of number
- Number
- Whole number
- Numerator
- Denominator
Everything is calculated in your browser, so results appear instantly and nothing you type is sent to a server.
How it works
The number is written as an exact fraction and inverted. The product of a number and its reciprocal is always 1.
Formula
Reciprocal of x = 1/x; of a/b = b/a
Worked example
Inputs — Type of number: An integer or decimal; Number: 8.
Results — Reciprocal (fraction) = 1/8; Reciprocal (decimal) = 0.125; As a mixed number = 1/8; Steps = 1. Write the number as a fraction: 8
2. Swap numerator and denominator: 1/8
3. Check: 8 × 1/8 = 1.
Key terms
- Reciprocal
- 1 divided by a number.
Frequently asked questions
What is the reciprocal of 8?
1/8 = 0.125.
What is the reciprocal of 2/5?
5/2 = 2.5.
What is the reciprocal of a negative number?
Also negative: the reciprocal of −4 is −1/4.
Which number is its own reciprocal?
1 and −1.