A familiar situation
When scaling a recipe, add or divide ingredient fractions and reduce the result before measuring.
How to use this calculator
- Enter first numerator, first denominator, operation and the remaining inputs.
- Select Calculate to see the answer and its breakdown.
- Keep a scenario, change an input and compare the results.
Use consistent units and check the assumptions below before applying the result.
How fraction is calculated
Fractions are normalized by a greatest-common-divisor reduction. Addition and subtraction use a common denominator; multiplication multiplies corresponding terms; division multiplies by the reciprocal. For 2/3 + 1/4, use denominator 12: 8/12 + 3/12 = 11/12.
a/b ± c/d = (ad ± bc)/bd; (a/b)(c/d)=ac/bd; (a/b)/(c/d)=ad/bc.For 2/3 + 1/4, use denominator 12: 8/12 + 3/12 = 11/12.
Assumptions & useful context
The result depends on the values you enter and the method described above. Displayed numbers may be rounded; calculations use the unrounded values. Check that this model matches your situation before relying on it.
Frequently asked questions
Will the answer be reduced?
Yes, numerator and denominator are divided by their greatest common divisor.
Can I divide by a zero fraction?
No. A zero divisor is rejected because the quotient is undefined.