Ratio & Proportion
Solve a simple proportion with a missing value.
Solve a simple proportion with a missing value.
Solve a simple proportion with a missing value. Fill in the fields above and the result updates instantly, together with the formula behind it.
Missing value = B × C ÷ A
If 3 units correspond to 12, then 5 units correspond to 20.
Useful for recipes, map scales and proportional quantities.
Missing value = B × C ÷ A. Example: If 3 units correspond to 12, then 5 units correspond to 20.
You enter: First value; Matching value; New first value. An example value is shown in each empty field, and the result appears as soon as the numbers are valid.
Enter the known pair (for example 3 cups for 12 servings) and the new value on the first side (5 cups); the missing value is B × C ÷ A = 20 servings.
Yes. Use Copy to copy the result or full example. Share creates a link that puts your chosen values into the URL fragment so another person can reproduce the calculation. Your named saves and recent history stay in your own browser.