A ratio is in simplest form when its terms are whole numbers that share no common factor other than 1. Simplifying doesn’t change what the ratio says — 18 : 24 and 3 : 4 describe exactly the same relationship — but the smaller numbers are easier to read, compare and scale. This simplifier works with two or more terms and accepts decimals and fractions, clearing them first so the result is always in whole numbers.
How to use the ratio simplifier
- Type the ratio with colons between terms, such as
18:24,2.4 : 3.6,12:18:30or1/2 : 3/4. You can also write5 to 8. - The simplest form appears on the tape along with the greatest common factor and, if needed, the multiplier used to clear decimals or fractions.
- The tape also gives the unit-ratio form (1 : n) and, for two-term ratios, the n : 1 form and the matching fraction.
- A table lists the first ten equivalent ratios, handy for checking answers on a worksheet.
How ratio simplification works
With decimals, first multiply by 10, 100 or 1,000 — enough to remove every decimal point. With fractions, multiply by the least common multiple of the denominators. Both steps keep the ratio equivalent because every term is multiplied by the same number.
Worked example: 2.4 : 3.6
Clear decimals: multiply both terms by 10 → 24 : 36
Factor: 24 = 2³ × 3 and 36 = 2² × 3²
GCF: 2² × 3 = 12
Divide: 24 ÷ 12 = 2 and 36 ÷ 12 = 3, so the ratio is 2 : 3
Unit ratio: 1 : 1.5
Ratios with different units
Before simplifying, make sure every term uses the same unit. “30 minutes to 2 hours” is not 30 : 2 = 15 : 1. Convert first: 2 hours is 120 minutes, so the ratio is 30 : 120 = 1 : 4. Once the units match, they cancel, and the simplified ratio has no units at all.
Everyday ratios in simplest form
| Original | Simplest form | Where you see it |
|---|---|---|
| 1,920 : 1,080 | 16 : 9 | Widescreen video resolution |
| 1,024 : 768 | 4 : 3 | Older monitors and many tablets |
| 6,000 : 4,000 | 3 : 2 | DSLR camera photos |
| 250 : 750 | 1 : 3 | Concentrate to water |
| 45 : 15 | 3 : 1 | Students to adults on a field trip |
| 12 : 18 : 30 | 2 : 3 : 5 | A three-way split |
Tips and common mistakes
- Divide by the greatest common factor in one go. Dividing by smaller common factors repeatedly also works (18 : 24 → 9 : 12 → 3 : 4) but takes longer and makes it easy to stop too soon. The GCF calculator finds the largest one directly.
- Don’t simplify across a colon like a fraction. In 2 : 3 : 5 the GCF must divide all three terms; cancelling only two of them changes the ratio.
- Keep the order. 3 : 4 and 4 : 3 are different ratios.
- Unit ratios may be decimals. 2 : 3 as a unit ratio is 1 : 1.5. That’s fine — unit ratios are for comparison, while simplest form is for whole-number answers.
Related tools
To find a missing term in a proportion or share a total in a ratio, use the ratio calculator. To turn a ratio into part-to-whole fractions and percentages, try the ratio to fraction calculator.
Frequently asked questions
How do you simplify a ratio?
Divide every term by the greatest common factor of all the terms. For 18:24 the GCF is 6, so the ratio simplifies to 3:4.
How do you simplify a ratio with decimals?
Multiply every term by the same power of ten to make them whole numbers, then divide by the GCF. 2.4:3.6 becomes 24:36 after multiplying by 10, and dividing by 12 gives 2:3.
How do you simplify a ratio with fractions?
Multiply every term by the least common multiple of the denominators. For 1/2 : 3/4, multiply by 4 to get 2:3, which is already in lowest terms.
Can I simplify a ratio with three parts?
Yes. Find the GCF of all three numbers and divide each by it. 12:18:30 has a GCF of 6 and simplifies to 2:3:5.
What is a unit ratio?
A ratio rewritten so one term is 1, such as 1 : 1.5 instead of 2 : 3. Unit ratios make comparisons easy, which is why gear and map scales are often written that way.