Ratio calculator
Simplify ratios, solve for missing values in proportions and distribute a total according to a given ratio.
- Free, no sign-up
- No data stored
- Reviewed 2026-01-15
Your details
Results
Simplified ratio
3 : 4
3 : 4
- As decimal
- 0.75
- As percent
- 75.00 %
- Share a
- 42.86 %
- Share b
- 57.14 %
- Missing value
- 20
3:4 = 15:20
- A3 · 42.9%
- B4 · 57.1%
Equivalent ratios
| Multiple | A | B |
|---|---|---|
| 1 | 3 | 4 |
| 2 | 6 | 8 |
| 3 | 9 | 12 |
| 4 | 12 | 16 |
| 5 | 15 | 20 |
| 6 | 18 | 24 |
| 7 | 21 | 28 |
| 8 | 24 | 32 |
| 9 | 27 | 36 |
| 10 | 30 | 40 |
About the Ratio Calculator
Enter a ratio to simplify it to lowest terms, solve a proportion (A:B = C:?), or divide a total amount according to a ratio. Useful for recipes, mixtures, scaling drawings and splitting costs.
How to use the Ratio Calculator
- Enter the ratio values (A and B).
- To solve a proportion, enter three of four values.
- To divide a total, enter the ratio and the total amount.
- View simplified ratio and solutions.
Frequently asked questions
How do I simplify a ratio?
Divide both parts by their greatest common divisor (GCD). For example, 12:8 → divide both by 4 → 3:2.
Can I use three-part ratios?
Enter values for A, B and optionally C/D. The tool simplifies and scales multi-part ratios.
How do I divide a total by a ratio?
Add the ratio parts (e.g. 3+2=5), then multiply total by each part/sum. £500 in 3:2 = £300 and £200.