Ratio Calculator

Simplify ratios, solve proportions, scale ratios, or split a total — four ratio tools in one.

Simplify a ratio to its lowest terms
:
Method: Divide both values by their Greatest Common Divisor (GCD)

How ratios work

A ratio compares two or more quantities. "3:2" means "3 parts of the first for every 2 parts of the second." Ratios appear in maps, recipes, finance, engineering, and everyday problem-solving.

Simplify (GCD method)
8:12 → GCD(8,12)=4 → 2:3
Find the greatest common divisor and divide both sides by it.
Proportion (cross-multiply)
3:4 = 9:? → ? = (9×4)÷3 = 12
Cross-multiply and divide to find the unknown term.
Scale a ratio
3:4 × 5 = 15:20
Multiply both terms by the same factor — the ratio remains equivalent.
Split a total
₹1000 in 2:3 → ₹400 & ₹600
Divide total by sum of parts (5), multiply each share: 2/5 and 3/5.

Common ratio uses in India

Partnership & Profit Sharing

If two partners invest in a 3:5 ratio, divide profits in the same ratio. Enter the total profit and ratio in the Split tool.

Map & Scale Drawing

A map scale of 1:50000 means 1 cm on the map equals 50000 cm (500 m) on the ground. Use the Scale or Proportion tool.

Recipe Scaling

A recipe for 4 people uses flour and sugar in 3:1. To scale for 10, use the Scale tool with factor 2.5 to get the new quantities.

Frequently asked questions

How do I simplify a ratio?

Find the Greatest Common Divisor (GCD) of both numbers and divide each by it. For example, 24:36 — GCD is 12, so the simplified ratio is 2:3. The Simplify tab above does this automatically, including for decimal inputs.

How do I work out a ratio between two numbers?

Write the two numbers separated by a colon (e.g. 150:200). Then simplify by dividing both by their GCD. 150:200 → GCD is 50 → simplified ratio is 3:4. This tells you the relationship between the two quantities in the simplest whole-number form.

How do I find the missing value in a proportion?

Use cross-multiplication. If A:B = C:D and D is unknown, then D = (B × C) ÷ A. For example 3:4 = 9:D gives D = (4 × 9) ÷ 3 = 12. The Solve Proportion tab handles any position — just leave one field blank.

What is the difference between a ratio and a fraction?

A ratio (3:4) compares two separate quantities to each other, while a fraction (3/4) expresses one quantity as a part of a whole. The ratio 3:4 means 3 parts to 4 parts (total 7 parts), whereas the fraction 3/4 means 3 out of 4 total parts.

How do I divide money in a given ratio?

Add up the ratio parts to get the total share count, then multiply the total money by each part's fraction. To split ₹1000 in 2:3: total parts = 5, so first person gets ₹1000 × 2/5 = ₹400, second gets ₹1000 × 3/5 = ₹600. The Split Total tab automates this.