Fraction to Percent Calculator

Converting a fraction to a percentage is one of the most common maths operations in everyday life — whether you are reading nutrition labels, calculating a test score, understanding a discount, or working through school homework. This calculator handles every input format: simple fractions like 3/4, mixed numbers like 1 2/5, plain decimals like 0.875, and even percentages entered in reverse (e.g. 75%) to verify or reformat a value. The result appears instantly as you type, along with the equivalent decimal, a simplified fraction, a 1-to-x ratio, and an interactive number-line diagram that places your value visually between 0% and 200%.

The formula

The conversion is a two-step calculation:

1. Divide the numerator by the denominator to produce a decimal: decimal = numerator / denominator
2. Multiply by 100 to shift the decimal point two places to the right: percent = decimal × 100

For a mixed number such as 1 3/4, add the whole part first: 1 + (3/4) = 1.75, then 1.75 × 100 = 175%.

For a fraction already expressed as a decimal (0.625), skip straight to step 2: 0.625 × 100 = 62.5%.

How the simplification works

When you enter a fraction, the calculator also finds the simplest equivalent form using the Euclidean greatest-common-divisor (GCD) algorithm. For example, 6/8 simplifies to 3/4 because gcd(6, 8) = 2, so both parts divide by 2. Seeing the simplest form alongside the percentage makes it easier to spot common fractions at a glance.

Worked example

Suppose a student scores 17 out of 25 on a quiz:

• Fraction: 17/25
• Decimal: 17 ÷ 25 = 0.68
• Percentage: 0.68 × 100 = 68%

Now suppose a recipe calls for 2 3/8 cups of a 3-cup maximum:

• Mixed number: 2 3/8 = 2 + 3/8 = 19/8 = 2.375
• Percentage of the maximum: 2.375 / 3 × 100 ≈ 79.17%

(For that second example you would enter the ratio 2.375/3 as a decimal: 0.79166... — or compute 2.375 / 3 separately first.)

All calculations run locally in your browser — no numbers are sent to any server.