What is a ratio calculator?
A ratio calculator is an online tool used to compare two or more quantities. It can simplify ratios, find equivalent ratios, and help solve ratio and proportion problems.
Ratio Calculator
Reduce ratios to simplest form or solve missing-value proportions for recipes, maps, mixing, and comparison problems.
Choose a ratio task
Simplify a ratio, or enter three known values in a proportion to find the missing fourth value.
About this calculator
How to use Ratio Calculator, plus the formulas and logic behind the results.
Tool description
The Ratio Calculator simplifies two-part ratios or solves a missing value in a proportion A : B = C : ?.
How to use
- Choose simplify mode or proportion mode.
- Enter values A and B (and C for proportion mode).
- Select Calculate to see the simplified ratio or missing value.
- Use Clear to restore the default example.
Formulas & reference
Simplify A : B by dividing both parts by gcdProportion: A : B = C : D ⇒ D = (C × B) ÷ ACross-check: A × D = B × C
Ratio and proportion basics
- A ratio compares two quantities
- Simplify by dividing both parts by their GCF
- Proportions: A/B = C/D
- Cross multiplication checks equivalent ratios
Calculation logic
Simplify mode scales decimal inputs to integers when needed, then divides by their GCD. Proportion mode solves for the fourth term and checks cross-multiplication equality.
For proportion mode, Value C corresponds to the scaled first term in A : B = C : ?.
Ratio Calculator FAQ
Common questions about this calculator and how to use the results.
How do you calculate a ratio?
To calculate a ratio, compare two quantities by dividing them by their greatest common factor when appropriate. For example, a ratio of 10 to 20 can be simplified to 1:2.
How do you simplify a ratio?
Divide every part of the ratio by the greatest common factor shared by all values. For example, 12:18 can be simplified to 2:3 by dividing both numbers by 6.
How do you find an equivalent ratio?
Multiply or divide every number in a ratio by the same nonzero value. For example, 2:3 and 4:6 are equivalent ratios.
How do you calculate the ratio between two numbers?
Write the two numbers in ratio form and simplify them if possible. For example, the ratio of 15 to 25 is 15:25, which simplifies to 3:5.
How do you convert a ratio to a fraction?
Add the parts of the ratio to determine the total, then use the relevant part as the numerator. For a ratio of 2:3, the first part represents 2/5 of the total.
How do you convert a ratio to a percentage?
Divide the part by the total number of parts and multiply by 100. For a ratio of 1:4, the first part represents 1 ÷ 5 × 100 = 20%.
How do you calculate a ratio from a percentage?
A percentage can be converted into a ratio by expressing it as a fraction of 100 and simplifying. For example, 25% is 25:100, which simplifies to 1:4.
How do you solve a ratio problem?
Identify the known quantities and write them as a ratio. Then simplify the ratio or use a proportion to find the unknown value.
How do you calculate a ratio with three numbers?
Write all three values in the same order and simplify them by dividing each value by their greatest common factor. For example, 6:12:18 simplifies to 1:2:3.
What is the difference between a ratio and a proportion?
A ratio compares two or more quantities, while a proportion states that two ratios are equal. For example, 2:3 is a ratio, while 2:3 = 4:6 is a proportion.
How can a ratio calculator be used in real-life situations?
Ratios are commonly used in recipes, maps, construction, finance, mixtures, sports statistics, and many other situations where quantities need to be compared or scaled.