Ratio Calculator
Optional — leave at 0 to just simplify the ratio.
Simplified ratio
2:3
Share A
200.00
Share B
300.00
A 2:3 ratio simplifies to 2:3. Splitting 500 in that ratio gives 200.00 to Share A and 300.00 to Share B.
Quick answer
A ratio calculator simplifies two numbers to their lowest terms by dividing both by their greatest common divisor, and splits a total amount proportionally between them. For example, simplifying 8:12 gives 2:3, and splitting $500 in that ratio gives $200 to one side and $300 to the other.
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Ratio Calculator is one of numbers, percentages and conversion tools on OneCalculate — see the full set for this category.
Browse MathsHow it works
A ratio compares two quantities side by side, written as A:B. This tool does two related jobs: it
simplifies a ratio to its lowest terms, and it splits a total amount proportionally between the two
parts.
Simplifying a ratio means dividing both sides by the largest number that divides evenly into each of them — their greatest common divisor (GCD). This calculator finds the GCD using the Euclidean algorithm, then divides both parts by it:
Simplified A = Part A ÷ GCD(Part A, Part B)
Simplified B = Part B ÷ GCD(Part A, Part B)For example, 8:12 has a GCD of 4 (since 4 × 2 = 8 and 4 × 3 = 12), so it simplifies to 2:3 — the same proportion, written with smaller numbers.
Splitting a total in a given ratio answers a different, related question: if you’re dividing an amount — money, ingredients, hours, anything — between two parties in a stated ratio, how much does each side get? The formula is:
Share = Total × (Part ÷ Sum of parts)So splitting $500 in a 2:3 ratio gives Part A a share of 500 × (2 ÷ 5) = $200, and Part B a share of 500 × (3 ÷ 5) = $300 — together adding back up to the full $500. Leave the total at 0 if you only want the simplified ratio and don’t need to split an amount.
Worked example
Jack and Priya are chipping in for a mate’s $500 milestone birthday present in Brisbane. Rather than split it straight down the middle, they agree it’s fairer to base it on how many guests each of them is bringing to the dinner afterwards — Jack is bringing 8 people, Priya is bringing 12.
That gives a starting ratio of 8:12. The greatest common divisor of 8 and 12 is 4 (4 × 2 = 8, 4 × 3 = 12), so dividing both sides by 4 simplifies the ratio to 2:3 — the same proportion, smaller numbers.
To work out each person’s share of the $500, apply the split formula using either version of the ratio:
- Jack’s share: 500 × (8 ÷ (8 + 12)) = 500 × (8 ÷ 20) = 500 × 0.4 = $200
- Priya’s share: 500 × (12 ÷ (8 + 12)) = 500 × (12 ÷ 20) = 500 × 0.6 = $300
Because 8:12 and 2:3 describe the same proportion, running the simplified ratio through the formula gives the identical answer: 500 × (2 ÷ 5) = $200, and 500 × (3 ÷ 5) = $300.
| Ratio (parts) | Share of $500 | |
|---|---|---|
| Jack (8 guests) | 2 | $200 |
| Priya (12 guests) | 3 | $300 |
Jack ends up paying $200 and Priya $300 — together, exactly the $500 owed, split in proportion to how many guests each of them is bringing.
Frequently asked questions
How do you simplify a ratio?
To simplify a ratio, find the greatest common divisor (GCD) of both numbers and divide each side by it. For example, the ratio 8:12 has a GCD of 4, so dividing both sides gives 2:3 — the simplest form, where no whole number bigger than 1 divides evenly into both parts.
How do you split money in a ratio?
Add the parts of the ratio together to get the total number of parts, then divide the amount you're splitting by that total to find the value of one part. Multiply that value by each side of the ratio to get each share. Splitting $500 in a 2:3 ratio gives $200 and $300.
What does a ratio of 1:1 mean?
A ratio of 1:1 means both quantities are exactly equal — an even, 50/50 split. If you're dividing a total amount in a 1:1 ratio, each side receives exactly half. It's the simplest possible ratio and represents perfect balance between the two parts being compared.
What's the difference between a ratio and a fraction?
A ratio compares two separate quantities to each other, like 2:3, while a fraction represents part of a single whole, like 2/5. A ratio of 2:3 can be rewritten as the fraction 2/5 of the total, since the two parts add up to 5 — related ideas, but not identical.
Can a ratio calculator simplify ratios that already can't be reduced?
Yes. If the two numbers share no common factor other than 1, like 5 and 7, the ratio is already in its simplest form, and the calculator simply returns it unchanged. Not every ratio can be reduced further, and that is a perfectly valid, expected result.
Does the order of the numbers in a ratio matter?
Yes. A ratio of 2:3 is not the same as 3:2 — the order shows which quantity corresponds to which part. When splitting an amount, the first number always sets Part A's share and the second sets Part B's share, so enter them in the correct order.
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Written and verified by Nirbhay Tripathi
Last updated 18 August 2026
All rates on this page are verified againstKhan Academy — Ratioson 18 August 2026. See our methodology for the full update calendar.