What is a ratio calculator?
A ratio calculator compares quantities in a fixed order and can reduce that relationship to simpler terms. It can also use equivalent ratios to solve proportions or split a total into proportional shares.
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How does the ratio calculator work?
For simplification, decimal terms are scaled to integers and divided by their greatest common divisor. Proportions use cross multiplication. Division by ratio adds the ratio parts, finds the value of one part, then multiplies that value by each term.
Ratio formulas
How to use the ratio calculator
- Select simplify, proportion, divide or compare.
- Enter a ratio using a colon.
- Enter the requested second ratio or total.
- Select Calculate Ratio and review the answer and steps.
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Ratio examples
12:18 simplifies to 2:3. If 2:3 = 8:x, cross multiplication gives x = 12. Dividing 100 in a 2:3 ratio gives shares of 40 and 60.
Ratio rules and limitations
Ratios must contain two finite terms. Both terms cannot be zero. In a proportion, the known values must not create division by zero. Use consistent units before comparing ratios.
Worked example: Ratio
Enter the following values in the Ratio Calculator and calculate to reproduce this result.
- Calculation type: Simplify a ratio
- Ratio: 12:18
Example result: 2:3. 12:18 simplifies to 2:3.
Calculation used: Divide both terms by their greatest common divisor.
How to interpret this example
Both terms are divided by their greatest common divisor, which is 6 for 12 and 18. The simplified ratio 2:3 preserves the relationship, not the original quantities. Keep the same unit basis before comparing two measured amounts.
Frequently asked questions about ratios
Methodology and calculation scope
The calculator scales finite decimal terms to integers where simplification is needed, uses an integer greatest-common-divisor calculation, and applies standard cross-multiplication and proportional-share formulas.