Math
Ratio Calculator
Use this ratio calculator to reduce a:b ratios, find the unit rate, and understand how two quantities compare.
Try an example
Result
Simplified ratio
—
- Unit rate a per 1 b
- —
- Unit rate b per 1 a
- —
Student quick launch
Grade planning, algebra checks, and formulas students reach for most.
Study path
Use this calculator with
Follow these when you want the formula behind the answer, a short lesson, or nearby tools in the same topic.
What the ratio calculator solves
Use this ratio calculator to reduce a:b ratios, find the unit rate, and understand how two quantities compare.
Formula
How to use it
- Enter the two quantities in the same or comparable units.
- Use whole numbers for exact ratio reduction.
- Use the unit rates when you need per-one comparisons.
How to read the answer
The simplified ratio keeps the same comparison with the smallest whole-number parts possible.
Common mistakes and edge cases
- Do not compare quantities in different units without converting first.
- A zero on one side can be valid, but 0:0 is not a meaningful ratio.
- Ratios describe relative size, not the total amount by themselves.
Worked examples
Simplify 12:18
Simplified ratio
2:3
Recipe scaling ratio
Simplified ratio
2:5
Frequently asked questions
Can a ratio include decimals?+
Yes, but integer ratios are easier to reduce exactly. Convert decimals to equivalent whole numbers when possible.
What does a unit rate mean?+
A unit rate tells how much of one quantity corresponds to exactly one of the other quantity.
About this calculator
- Written by
- mathcheck editorial team
- Last reviewed
- May 8, 2026
Method
- Uses the values entered by the user and stable formulas documented on the page.
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Last updated: May 8, 2026