Ratio Calculator
Ratio Calculator
Solve for the missing value in a ratio or proportion (A : B = C : D).
Leave EXACTLY ONE box empty to calculate its value.
:
=
:
Missing Value Is
0
What is a Ratio?
A Ratio compares two quantities and indicates how many times one value contains or is contained within the other. It is usually separated by a colon (:). When two ratios are set equal to each other (like A:B = C:D), it creates a proportion.
This calculator is perfect for scaling recipes, resizing images without losing proportions, mixing chemicals, or solving math homework.
Frequently Asked Questions
How does the calculator solve the missing value?
It uses the cross-multiplication method. In the proportion A/B = C/D, the cross products are always equal: A × D = B × C. By using simple algebra, the tool isolates the empty box and calculates the exact value.