How to use this calculator
The reciprocal is the value that multiplies your input to give 1. For a fraction, swap the numerator and denominator and then reduce. Decimals are first converted to exact fractions, allowing a result such as the reciprocal of 0.25 to stay exactly equal to 4.
The method
Enter the values in the labeled fields, check the units or selected mode, and choose Calculate. The result includes the applicable working and a breakdown or visual when useful. Change an input and calculate again to update the result.
Number or fraction: 3/4
Reciprocal: 4/3
The number that multiplies your input to make 1.
Scope and limitations
Zero is rejected because it has no reciprocal. The exact fraction is primary; the decimal display is approximate.
Common questions
Is a reciprocal the same as changing the sign?
No. The reciprocal of 2 is 1/2. Its additive inverse, or opposite, is -2.
Can a reciprocal be negative?
Yes. A negative input has a negative reciprocal, because their product must be positive 1.
References & further reading
External references provide background, not an endorsement of this implementation. See our methodology for numerical conventions and limitations.