Ratio and Proportion Calculator
Fill in the values and the answer updates as you type.
How the Ratio and Proportion Calculator works
Cross-multiply: x = b × c ÷ a.
Inputs and results
The Ratio and Proportion Calculator takes 3 inputs and gives 1 result.
What you enter
- A — starts at 2.
- B — starts at 5.
- C — starts at 6.
What you get
- X (if A is to B, then C is to X)
Example: Ratio and Proportion Calculator with the starting values
With a 2, b 5 and c 6, the calculator returns:
| X (if A is to B, then C is to X) | 15 |
|---|
Change any value above and the results update straight away.
Ratio and Proportion Calculator FAQ
How do I use the Ratio and Proportion Calculator?
Enter a, b and c in the fields, then read x (if a is to b, then c is to x) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Ratio and Proportion Calculator calculate?
Solve a : b = c : x. It returns x (if a is to b, then c is to x) from the 3 values you provide.
What values does the Ratio and Proportion Calculator start with?
It opens with a 2, b 5 and c 6 so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Ratio and Proportion Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Ratio and Proportion Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.