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Ratio Calculator

For a / b = c / x, the missing value is x = b × c / a. Both denominators and the first numerator must be nonzero.

Free to useNo sign-upRuns in your browser
Enter your details

Enter the inputs, then select Solve ratio.

Your result
Enter your details

Result will appear here

How Ratio Calculator works

For a / b = c / x, the missing value is x = b × c / a.

Both denominators and the first numerator must be nonzero. Decimal ratios are supported; results use ordinary floating-point arithmetic.

Concept diagram for Ratio Calculator, showing first ratio numerator input and the supported output.
Concept diagram; the three operation images are actual browser captures.

How to use Ratio Calculator

Start with your own input.

Enter first ratio numerator

Replace the example with your first ratio numerator.

Solve ratio
Input and settings
Ratio Calculator: input and settings in the implemented browser tool
Actual local browser view. Open the image to read it at full size.

Set the options

Set first ratio denominator, second ratio numerator.

Solve ratio
Tool result
Ratio Calculator: tool result in the implemented browser tool
Actual local browser view. Open the image to read it at full size.

Run and check the output

Select Solve ratio. Review the missing denominator in a proportion, then use Copy result or download the result file.

Solve ratio
Review the details
Ratio Calculator: review the details in the implemented browser tool
Actual local browser view. Open the image to read it at full size.

When to use Ratio Calculator

Solve an unknown ratio term

To solve an unknown ratio term, start with first ratio numerator. For a / b = c / x, the missing value is x = b × c / a.

Solve ratio
Abstract input values and a mathematical worksheet.
Start with the values. Concept illustration.

Scale a recipe proportion

To scale a recipe proportion, start with first ratio numerator. Both denominators and the first numerator must be nonzero.

Solve ratio
Two calculation examples shown for comparison.
Compare a second example. Concept illustration.

Check a proportional allocation

To check a proportional allocation, start with first ratio numerator. Review the missing denominator in a proportion, then use Copy result or download the result file.

Solve ratio
A calculation and supporting explanation represented conceptually.
Explain the calculation. Concept illustration.

How to read the result

Check what the output means.

The missing denominator in a proportion. For a / b = c / x, the missing value is x = b × c / a.

Both denominators and the first numerator must be nonzero. Decimal ratios are supported; results use ordinary floating-point arithmetic.

Solve ratioSolve ratio
A mathematical result connected to the values used to calculate it.
Read the result with its inputs. Concept illustration.

Supported input and limits

Check the format before processing.

Both denominators and the first numerator must be nonzero. Decimal ratios are supported; results use ordinary floating-point arithmetic.

Inputs and results are handled in this browser.

Solve ratioSolve ratio
Values and units reviewed before relying on a mathematical result.
Check values and units. Concept illustration.

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Solve ratio with your input

Review the missing denominator in a proportion, then use Copy result or download the result file.

Solve ratio

Ratio Calculator: common questions

Answers about using Ratio Calculator and understanding its results.

What does this tool support?

Both denominators and the first numerator must be nonzero. Decimal ratios are supported; results use ordinary floating-point arithmetic.

Can I save the result?

Yes. Download the result file after processing. Text results also have Copy result. Processing uses local browser code; no account is required.