Ratio Calculator
FreeCalculate and simplify ratios or find the missing value in a proportion
About Ratio Calculator
Ratios show up everywhere from recipes to scale drawings to mixing solutions, and the two common headaches are simplifying a messy ratio and finding the one missing value in a proportion. This calculator does both, so you can reduce a ratio to its cleanest form or solve for the unknown without scribbling cross-multiplication on the side.
Enter your ratio to simplify it, or fill in three parts of a proportion to find the fourth. It's free, runs in your browser, and needs no signup. By handling the arithmetic for you, it turns scaling recipes, adjusting mixes, or working out proportional problems into a quick, reliable answer rather than a chance to make a mistake.
Common uses
- Simplifying a ratio to its smallest whole-number form
- Scaling a recipe up or down while keeping proportions
- Finding a missing value in a proportion problem
- Adjusting mix ratios for paint, fuel, or solutions
How to use
- 1
Configure options
Set your preferences using the options panel below.
- 2
Click Generate
Click the process button to generate your result instantly.
- 3
Copy or download
Copy the result to clipboard or download it directly to your device.
Why ToolHub?
- 100% Free — no account needed
- Works in your browser — no software required
- Instant results
- Secure and private
- No data stored
- Simple to use
FAQ
Can it find a missing number in a proportion?
Yes. Enter three of the four values and the calculator solves for the missing one using cross-multiplication.
Does it reduce ratios automatically?
Yes, it simplifies a ratio to its lowest whole-number terms so it's easy to read and use.
Can I use decimals in my ratio?
You can enter decimal values, and the tool will work out the simplified ratio or missing value from them.
Can I use Ratio Calculator on mobile?
Yes — ToolHub is fully responsive and works on iPhone, Android, tablets and all modern browsers. No app install needed.