Fractions, Ratios & Proportions
4 tools in this collection — free, instant, and private in your browser.
Fractions, ratios, and proportions appear constantly in everyday life — scaling a recipe, mixing paint colors, reading a map, calculating discounts, or solving a math problem for school. These four focused calculators handle the most common tasks quickly and accurately, without requiring you to remember the rules for cross-multiplication or lowest common denominators.
A fraction expresses a part of a whole. Converting a fraction to its decimal equivalent — for example, recognizing that 3/8 is 0.375 — is useful whenever you need to compare fractions of different denominators or enter a value into a calculator that expects decimals. The fraction-to-decimal converter handles any numerator and denominator instantly.
A ratio describes the relationship between two or more quantities. Ratios can be written as 3:2, 3 to 2, or 3/2, but they all convey the same idea. The ratio calculator lets you work with ratios of any size, and the ratio simplifier reduces a ratio to its lowest terms by finding the greatest common divisor — so 12:8 becomes 3:2, which is easier to read and communicate.
A proportion is an equation that states two ratios are equal. Solving a proportion — finding the missing fourth value when three are known — is one of the most common applied math operations. If a recipe calls for 2 cups of flour for 24 cookies and you want to make 60, the proportion solver finds that you need exactly 5 cups. The same logic applies to unit conversions, scale drawings, and many science and engineering problems.
- Use the Fraction to Decimal Calculator when comparing fractions or entering values into a calculator.
- Use the Ratio Simplifier to reduce any ratio to its clearest form.
- Use the Proportion Solver when you know three values in a ratio equation and need the fourth.
- Use the Ratio Calculator to work with multi-part ratios or scale values up and down.
These tools are intentionally simple — enter your numbers and get a clear answer. They are equally useful for a student working through a math worksheet and an adult scaling a recipe or mixing materials in the right proportions.
All fractions, ratios & proportions
All calculator tools →Compare these tools
| Tool | What it does |
|---|---|
| Fraction to Decimal Calculator | Convert any fraction (numerator/denominator) to a decimal number. |
| Proportion Solver | Solve proportions of the form A/B = X/C for the unknown X. Instantly find the missing value in any proportion. |
| Ratio Calculator | Simplify a ratio to its lowest terms or scale a ratio by a multiplier. Useful for mixing, recipes, maps, and more. |
| Ratio Simplifier | Simplify any ratio a:b to its lowest terms using the GCD. |
Frequently asked questions
- What is the difference between a ratio and a fraction?
- A fraction always represents a part of a single whole, where the denominator is the total number of equal parts. A ratio compares two or more separate quantities to each other and does not necessarily add up to a whole. For example, a ratio of 3:2 might describe the relationship between cups of water and cups of flour in a recipe, where neither is a subset of the other. In many cases the math looks identical, but the interpretation is different.
- How do I solve a proportion with a missing value?
- Set up two equal fractions with the missing value as x, then cross-multiply and divide. For example, if 4 is to 10 as x is to 25, you write 4/10 = x/25, cross-multiply to get 10x = 100, then divide both sides by 10 to find x = 10. The proportion solver does this automatically when you enter the three known values and indicate which position is missing.
- Why would I need to simplify a ratio?
- Simplified ratios are easier to interpret, communicate, and scale. A ratio of 48:36 conveys the same relationship as 4:3, but 4:3 is much easier to work with mentally. Simplification also makes it easier to spot when two ratios are equivalent, which matters in cooking, construction, and any field where you are scaling measurements. The simplifier divides both sides of the ratio by their greatest common divisor to reach the smallest whole-number form.