Free Ratio Calculator – Simplify & Solve Proportions
Simplify ratios instantly or solve one missing value in A:B = C:D with a free ratio calculator using cross-multiplication.
Use Simplify ratio when you know both quantities and want the smallest equivalent comparison. Use Solve proportion when one value in two equivalent ratios is missing. Both questions rely on the same proportional relationship, but the inputs and steps are different.
How it works
Simplify integer a:b by dividing both values by their greatest common divisor. In equivalent proportions a:b = c:d, cross multiplication gives a × d = b × c.
Example
Simplify 18:24 by dividing both numbers by 6 to obtain 3:4. To solve 2:3 = 8:x, calculate 2x = 3 × 8, so x = 12.
How to use
- Select Simplify ratio and enter both known amounts, such as 18 and 24, when you only need an equivalent reduced pair.
- Select Solve proportion when exactly one value of two equivalent ratios is missing and provide the other three values.
- Check the result by cross multiplying both sides; convert measurements to the same unit before comparing them.
Key features
- Two tasks: reduce a ratio or solve an equivalent proportion
- Greatest-common-divisor and cross-multiplication examples
- Input-based calculations with explicit mathematical checks
Common uses
- Scale recipe ingredient quantities
- Compare equivalent drawing scales
- Check school proportion problems
Limitations to know
Ratios require compatible measurement units. Convert kilograms to grams or metres to centimetres before comparison. A denominator of zero cannot be used in cross multiplication to solve by division, and decimal results may need rounding.
Frequently asked questions
How do I simplify 18:24?
The greatest common divisor is 6. Divide 18 and 24 by 6 to obtain the equivalent ratio 3:4.
How do I find x in 2:3 = 8:x?
Cross multiply: 2 × x = 3 × 8, so x = 24 ÷ 2 = 12.
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