Ratio Calculator
Simplify a ratio to its lowest terms, or divide an amount (money, ingredients, paint) between two or three parts in a given ratio.
Ratio Calculator
How to simplify a ratio
- If any part has decimals, multiply all parts by the same power of 10 to make them whole numbers.
- Find the greatest common factor (GCF) of all the parts.
- Divide each part by the GCF.
Example: 45:60:75. The GCF is 15, so the ratio simplifies to 3:4:5.
Common ratios
| Use | Ratio | Meaning |
|---|---|---|
| Widescreen TV and video | 16:9 | 16 units wide for every 9 tall (1.78:1) |
| Concrete mix (cement:sand:gravel) | 1:2:3 | A general-purpose mix by volume |
| Two-stroke fuel mix | 50:1 | 50 parts gasoline to 1 part oil, or 2.6 oz of oil per gallon |
| Pour-over coffee | 1:16 | 1 g of coffee to 16 g of water |
| Golden ratio | 1:1.618 | A proportion common in design |
Ratios, fractions and percentages
A ratio of 2:3 means the whole has 5 parts. The first item is 2/5 = 40% of the total and the second is 3/5 = 60%. Note that 2:3 is not the same as the fraction 2/3. The fraction compares one part to the other, while the share of the whole is 2/5.
Frequently asked questions
How do you simplify a ratio?
Divide every part by their greatest common factor. For 24:36 the greatest common factor is 12, so the ratio simplifies to 2:3.
How do you simplify a ratio with decimals?
Multiply every part by 10, 100 or 1,000 until they're all whole numbers, then simplify. 1.5:2.25 becomes 150:225, which simplifies to 2:3.
How do you split an amount in a ratio?
Add the parts of the ratio, divide the total by that sum to get the value of one part, then multiply. To split $120 in the ratio 2:3, there are 5 parts, so one part is $24 and the shares are $48 and $72.
What does a ratio of 1:n mean?
It shows how many of the second item there are for every one of the first. 2:5 written as 1:n is 1:2.5. Screen aspect ratios and map scales are often written this way.
See also
- Proportion Calculator: Solve A/B = C/D for the missing number, with steps.
- Percentage Calculator: Percent of a number, percent change, and increase or decrease by a percent.
- Concrete Calculator: Cubic yards and bag counts for slabs, footings and columns.
Last updated: November 4, 2026