Ratio Calculator
Type a ratio like 12:18 and get it in lowest terms, as a fraction, a decimal and a percent. Scale it to any total, or check whether two ratios match.
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- Decimals welcome
- Scale to a total
- Free
Simplify a ratio
Scale the ratio
Uses the ratio above. Give a total, or a value for one side.
How to simplify a ratio
Find the greatest common factor
For 12:18 the biggest number that divides both is 6. GCF calculator →
Divide both sides by it
12 ÷ 6 = 2 and 18 ÷ 6 = 3, so 12:18 = 2:3.
Read it other ways
2:3 is the fraction 2/3 ≈ 0.667, and out of a whole it is 40% to 60%.
Questions people ask
How do you simplify a ratio?
Divide both numbers by their greatest common factor. 12:18 has a GCF of 6, so it simplifies to 2:3.
Can a ratio have decimals?
Yes. Multiply both sides by 10, 100 and so on until they are whole numbers, then simplify. 1.5:0.5 becomes 15:5, which is 3:1. The calculator does this automatically.
How do I split an amount in a ratio?
Add the ratio parts to get the number of shares, divide the amount by that, then multiply by each part. $150 in 2:3 is 5 shares of $30, so $60 and $90.
What is the difference between a ratio and a fraction?
A ratio 2:3 compares two parts to each other. The fraction 2/3 is the first part divided by the second. Both describe the same relationship; the fraction of the whole is different again (2/5 and 3/5).
How do I check if two ratios are equal?
Simplify both. If they reduce to the same ratio they are equal. Or cross-multiply: 2:3 and 6:9 are equal because 2 × 9 = 3 × 6. The proportion calculator does this.
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