How do I simplify a ratio?
Divide both sides by their greatest common divisor. 12:18 both divide by 6, giving 2:3 — the simplest form.
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Ratio calculator
Simplify a ratio to its lowest terms.
a:b ÷ gcd(a,b) = simplest ratio
Frequently asked questions
What does a ratio actually mean?
It compares two quantities by how many parts each has. 2:3 means for every 2 of the first thing there are 3 of the second.
Is 2:3 the same as 12:18?
Yes — they are equivalent ratios. Simplifying does not change the relationship, only the size of the numbers used to describe it.
Where is this used in real life?
Cooking — mixing rice and water 1:2 means 1 cup rice to 2 cups water. Maps and models — a 1:100 scale means 1 cm on paper is 100 cm in reality. Mixing — petrol-to-oil at 50:1 for a two-stroke engine. Sharing — splitting $50 in the ratio 2:3 gives $20 and $30.
What do the squares show?
Each coloured square is one part. Counting the two colours shows the simplified ratio visually, so 2:3 appears as 2 squares beside 3.