Ratio & Proportion Calculator
Simplify and compare ratios, solve proportions, and scale quantities with live steps.
Workspace
Preparing allocation and comparison tools…
Reduce and expand
Understand the ratio
Examples
Use colons, commas, semicolons, or spaces. Up to 12 parts.
Multiply the simplified ratio by any value greater than zero.
Every part is multiplied by the same value, so the relationship stays unchanged.
GuideHow to use
- Choose whether to simplify, solve a proportion, scale quantities, or compare two ratios.
- Enter ratio parts with colons, commas, semicolons, or spaces; results update as you type.
- Review the calculation and shares, then copy the result or download scaled quantities as CSV.
HelpFrequently asked questions
How do I solve a proportion like a:b = c:d?
Enter three of the four values and leave the one you want to find blank. The system cross-multiplies to solve for the missing value.
How do I simplify a ratio?
Enter the ratio parts separated by colons or commas, such as 8:12, and the system divides every part by their greatest common divisor.
How do I scale a recipe or mixture ratio to a real quantity?
Use scale quantities: enter the ratio, then either a known total to split across all parts, or one known part's actual value to scale the rest.
How can I tell whether two ratios are equivalent?
Compare the two ratios. Equivalent ratios have the same quotient when the first part is divided by the second, such as 4:6 and 10:15.
Can a ratio contain zero?
A part may be zero as long as not every part is zero. When comparing two ratios, the second part must be non-zero because it is used as the divisor.
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