How to use the Ratio Calculator
The ratio calculator solves proportions such as A : B = C : D.
What you need to enter
- A
- B
- C
- D (leave empty to solve)
The formula
D = B × C ÷ A. The ratio is simplified by dividing both parts by their GCF.
Worked example
Using the default values in the calculator:
- A: 3
- B: 4
- C: 9
| D | 12 |
| Ratio A:B | 3 : 4 |
| Scale factor | 3 |
Tips for better results
- Keep units consistent.
- Use it to scale recipes.
Common mistakes to avoid
- Putting values in the wrong order.
- Dividing by zero.