Ratio Calculator
Solve proportions of the form A : B = C : D.
2 : 5 = 8 : D
20
Enter three values of a proportion and the fourth is calculated automatically.
How to use
- Enter values for A, B and C.
- D is solved so that A : B = C : D.
- Adjust any field to recalculate.
Frequently asked questions
- How is D calculated?
- Using cross-multiplication: D = B × C ÷ A.
- Can I scale a recipe?
- Yes — put the known ratio in A : B and your new amount in C.