Ratio Calculator
Simplify ratios, solve missing values in proportions, and scale quantities instantly. Useful for cooking, maps, finance, and mathematics.
Ratio
3:4
Find D when
What Is a Ratio?
A ratio compares two or more quantities to show their relative sizes. Written as A:B or A/B, it expresses how many times one value contains another. Ratios appear everywhere: ingredient proportions in recipes, aspect ratios on screens, financial metrics like debt-to-equity, and map scales.
A proportion states that two ratios are equal (A:B = C:D). When one of the four values is unknown, cross-multiplication solves for the missing term — a technique used constantly in scaling, unit conversion, and probability.
Real-World Ratio Examples
- →Recipe scaling: A cake recipe calls for flour:sugar at 3:1. To make a larger batch with 600 g flour, you need 200 g sugar.
- →Map reading: A map scale of 1:50,000 means 1 cm on the map = 50,000 cm (500 m) in real life.
- →Screen aspect ratio: A 16:9 display that is 1920 px wide is 1080 px tall (1920 ÷ 16 × 9 = 1080).
- →Finance: A price-to-earnings ratio of 20:1 means investors pay $20 for every $1 of earnings.
Frequently Asked Questions
What is a ratio?▼
A ratio compares two quantities showing their relative size. Written as A:B, it tells you how many units of A exist for every unit of B.
How do you simplify a ratio?▼
Divide both numbers by their Greatest Common Divisor (GCD). For example, 12:8 → GCD is 4 → simplified to 3:2.
What is a proportion?▼
A proportion states two ratios are equal: A/B = C/D. Solve for a missing value using cross-multiplication: A×D = B×C.
What is the difference between ratio and fraction?▼
A fraction represents a part of a whole (2/5 of a pizza). A ratio compares two separate quantities (2 apples to 5 oranges). Though they look similar, their meanings differ.