Simplify a ratio, split a number by a ratio, or turn a ratio into a fraction, a decimal and percentage shares. Everything runs in your browser; nothing you enter is uploaded.
Simplify a ratio
Enter two or more parts separated by colons, for example 12:18 or 24:36:48.
Divide a number by a ratio
For example, divide 100 by 2:3 to get 40 and 60.
Ratio as a fraction, decimal and shares
Enter a two-part ratio, for example 3:4.
Worked example
Simplify 12:18. The greatest common divisor of 12 and 18 is 6. Divide both parts by 6: 12 / 6 = 2 and 18 / 6 = 3, so 12:18 simplifies to 2:3.
Simplify 24:36:48. The greatest common divisor of 24, 36 and 48 is 12. Divide each part by 12: 24 / 12 = 2, 36 / 12 = 3 and 48 / 12 = 4, so 24:36:48 simplifies to 2:3:4.
Divide 100 by 2:3. Add the parts: 2 + 3 = 5. Each part is worth 100 / 5 = 20. So the shares are 2 x 20 = 40 and 3 x 20 = 60.
Convert 3:4. As a fraction it is 3/4, which equals 0.75 as a decimal. As shares of the total, 3 out of 7 is about 42.9% and 4 out of 7 is about 57.1%.
How to use this calculator
- To simplify, type a ratio with colons between the parts, such as 12:18, then click Simplify ratio.
- To divide a number, type the number and the ratio, such as 100 and 2:3, then click Divide by ratio.
- To convert, type a two-part ratio, such as 3:4, then click Convert ratio to see the fraction, decimal and percentage shares.
- Use Clear to reset a section and start again.
How it works
A ratio compares two or more amounts. For example, 2:3 means that for every 2 of the first amount, there are 3 of the second.
To simplify a ratio, find the greatest common divisor, or GCD. In plain words, the GCD is the largest whole number that divides every part of the ratio without leaving a remainder. Divide every part by that number, and you get the same ratio in its simplest form. For 12:18, the largest number that divides both 12 and 18 is 6, so dividing by 6 gives 2:3.
To divide a number by a ratio, add the ratio parts to find the total number of parts, divide the number by that total to find the value of one part, then multiply by each ratio part. To turn a ratio such as 3:4 into a fraction, write the first part over the second part: 3/4. Divide to get the decimal, 0.75. To find each share as a percentage, divide each part by the total of the parts and multiply by 100.
Frequently asked questions
What is a ratio?
A ratio compares amounts. The ratio 2:3 means the first amount is 2 parts and the second amount is 3 parts of the same whole.
Can I simplify a ratio with more than two numbers?
Yes. Enter as many parts as you need, separated by colons, such as 24:36:48, which simplifies to 2:3:4.
Can I use decimals in a ratio?
Yes. The calculator handles decimals by converting them to whole numbers first, then simplifying in the usual way.
What happens if I leave a box empty?
The calculator shows a short prompt asking you to enter the missing value. It does not show NaN or a broken result.
Can a ratio part be zero or negative?
No. This calculator asks for parts greater than zero, because a ratio part of zero or less does not describe a share of a total in this tool.
What is the difference between a ratio and a fraction?
A ratio such as 3:4 compares one part with another part, while the fraction 3/4 is the first part divided by the second. The shares of the total are different: 3 out of 7 is about 42.9% and 4 out of 7 is about 57.1%.