How to use the Ratio Calculator
- Enter A and B for the known ratio.
- Enter C to find the matching value.
- Read the missing value, the simplified ratio and each part's share.
How it's calculated
Show the formula
A : B = C : x → x = B × C ÷ A
Handy for scaling recipes, mixing ratios and dividing profit between partners.
Worked example
These are the example numbers the calculator opens with. Change any of them above to see your own result.
You enter
| A | 3 |
|---|---|
| B | 5 |
| C | 12 |
You get
| 3 : 5 = 12 : ? | 20 |
|---|---|
| Simplified A : B | 3 : 5 |
| A as % of total | 37.5% |
| B as % of total | 62.5% |
Tips
- Great for scaling recipes, mixing concrete or paint, and sharing profit between partners.
Frequently asked questions
How do I divide money in a ratio?
Add the parts, then multiply the total by each part's share. For 3:5, partner A gets 3/8 and partner B gets 5/8.
How do I simplify a ratio?
Divide both sides by their highest common factor: 12:18 becomes 2:3.