Calculator Tools
Simplify a two-part ratio, solve one missing value in a proportion, or divide a total into two proportional shares. See the greatest common divisor or calculation steps with deterministic decimal formatting.
Simple workflow
How to use Ratio & Proportion Calculator
- 1Choose Simplify ratio, Solve a proportion or Divide a quantity.
- 2Enter the labelled terms. In a proportion, leave exactly one value empty.
- 3Select Calculate and review the simplified ratio, missing value or proportional shares and steps.
Good to know
Frequently asked questions
What is the difference between a ratio and a fraction?
A ratio compares two quantities, while a fraction commonly describes a part of a whole. Both can use similar notation and can be simplified by dividing terms by a common factor.
Can a simplified ratio contain zero?
Yes. 0:5 simplifies to 0:1, and 5:0 simplifies to 1:0. The ratio 0:0 is undefined and is rejected.
Which proportion value can be unknown?
Any one of a, b, c or d can be left empty in a ÷ b = c ÷ d. Leave exactly one value empty. A denominator cannot be zero.
Can I divide a total using three or more ratio terms?
Not in this version. Divide a quantity supports two positive whole-number ratio parts and shows both shares.
Practical guide
Simplify comparisons, solve equivalent ratios and split totals
A ratio compares quantities, while a proportion states that two ratios are equivalent. Simplifying divides both terms by their greatest common divisor. Solving a proportion uses cross multiplication with exactly one missing value.
Dividing a total by a ratio first adds the ratio terms to find the number of parts, finds the value of one part, then multiplies by each term. This version handles two-part division.
Worked example
Use each calculation mode
- Start with
- 24:36; 2/3 = 8/x; and a total of 300 divided in 2:3.
- Choose
- Choose the relevant mode and enter its labelled values.
- You get
- The simplified ratio is 2:3, x is 12, and the shares are 120 and 180.
Tips for a useful result
- Use whole numbers, including zero, when simplifying; 0:0 is undefined.
- Leave exactly one proportion field empty and never use zero as a denominator.
- Check whether the quantities use compatible units before comparing them.
Decimal results and privacy
Proportion and total-division inputs can use ordinary decimal notation. Calculations use exact decimal fractions internally and display a rounded result only when the fraction does not terminate within the shown precision.
Values and results stay in page memory and are not added to URLs, storage or analytics.
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