How do I simplify a ratio?

Divide both sides by their greatest common divisor. 18:24 both divide by 6, giving 3:4.

How do I solve a ratio with a missing number?

Cross-multiply. For 3:4 = 9:x, multiply 4 × 9 = 36 and divide by 3, so x = 12.

How do I convert a ratio to a percentage?

Divide the first number by the total of both parts and multiply by 100. In 3:4 the first part is 3 ÷ 7 × 100 = 42.86%, and the second is 57.14%.

How do I scale a ratio up or down?

Multiply both sides by the same number. 3:4 doubled is 6:8; halved it is 1.5:2. The relationship stays identical.

What is the difference between a ratio and a fraction?

A ratio compares two parts to each other (3:4 means 3 for every 4). A fraction compares a part to the whole (3/7 of the total). Same numbers, different bases.

How do I split an amount in a given ratio?

Add the parts to get the total number of shares, divide the amount by that, then multiply by each part. Splitting $700 in 3:4 gives 7 shares of $100, so $300 and $400.

Percentage Calculator / Ratio calculator

Ratio Calculator

Simplify a ratio to its lowest terms, solve for a missing value, turn a ratio into percentages, or split an amount into shares. Free, ad-free, and every answer updates as you type.

Simplify and solve

Simplify a ratio

Reduce:

3:4

Solve A : B = C : ?

:=: ?

Ratios as percentages and shares

Ratio to percentage

The ratio:as percentages

42.86% and 57.14%

Split an amount by a ratio

Splitin the ratio:

300 and 400

How to work with ratios step by step

A worked example using 18:24.

1. Find what divides both sides
6 divides 18 and 24
2. Divide both sides by it
18 ÷ 6 = 3, 24 ÷ 6 = 4 → 3:4
3. Add the parts for the total
3 + 4 = 7 shares
4. Convert to percentages
3 ÷ 7 = 42.86%, 4 ÷ 7 = 57.14%

To solve a proportion, cross-multiply: for 3:4 = 9:x, x = 4 × 9 ÷ 3 = 12. Scaling works the same way — multiply both sides by the same number and the ratio is unchanged.

Ratio, fraction, percentage — same numbers, different bases

A ratio of 3:4 compares two parts to each other. As a fraction of the whole it is 3/7, and as a percentage 42.86%. Mixing the bases is the usual mistake: 3:4 is not 3/4 or 75%.

Ratios show up everywhere numbers get shared or scaled — splitting a bill unevenly, mixing paint or concrete, scaling a recipe, screen aspect ratios, or dividing profit between partners. In every case the method is the same: add the parts, find one share, then multiply back out.

Common ratio answers

Simplified ratios and their percentage equivalents.

Simplify 18:243:4

Simplify 20:502:5

Simplify 45:603:4

Simplify 100:2502:5

Simplify 16:916:9

Simplify 12:361:3

1:1 as percentages50% / 50%

1:2 as percentages33.33% / 66.67%

1:3 as percentages25% / 75%

2:3 as percentages40% / 60%

3:4 as percentages42.86% / 57.14%

$700 split 3:4$300 and $400

Ratio questions people ask

How do I simplify a ratio?: Divide both sides by their greatest common divisor. 18:24 both divide by 6, giving 3:4.
How do I solve a ratio with a missing number?: Cross-multiply. For 3:4 = 9:x, multiply 4 × 9 = 36 and divide by 3, so x = 12.
How do I convert a ratio to a percentage?: Divide the first number by the total of both parts and multiply by 100. In 3:4 the first part is 3 ÷ 7 × 100 = 42.86%, and the second is 57.14%.
How do I scale a ratio up or down?: Multiply both sides by the same number. 3:4 doubled is 6:8; halved it is 1.5:2. The relationship stays identical.
What is the difference between a ratio and a fraction?: A ratio compares two parts to each other (3:4 means 3 for every 4). A fraction compares a part to the whole (3/7 of the total). Same numbers, different bases.
How do I split an amount in a given ratio?: Add the parts to get the total number of shares, divide the amount by that, then multiply by each part. Splitting $700 in 3:4 gives 7 shares of $100, so $300 and $400.

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