Percent to Fraction Calculator
Turning a percentage back into a fraction is the reverse of the familiar divide-and-multiply rule, and it is just as systematic. Because percent means parts per hundred, every percentage starts life as a fraction over 100, so the first step is simply to write the number above 100. The second step is to reduce that fraction to its lowest terms by dividing the numerator and the denominator by their greatest common divisor, the largest whole number that divides both exactly. For 75 percent you write 75/100, find that 25 divides both, and arrive at 3/4. This calculator does both steps for you and shows the reduced fraction alongside the decimal form, so you can see how the percentage breaks down. It handles whole-number percentages like 75 percent, decimal percentages like 12.5 percent, which it scales to 125/1000 before reducing to 1/8, and percentages above 100, which become improper fractions such as 150 percent equaling 3/2. Use it to simplify measurements, read probabilities as fractions, or check schoolwork. Every result is computed deterministically from the method shown below, with a worked example that reconciles exactly to the calculator defaults so you can follow the reduction and trust the simplest form it produces.
Write the percent over 100 and reduce: fraction = percent / 100, in lowest terms. So 75% is 75/100, which reduces to 3/4 (decimal 0.75).
Percent to fraction method
Step 1: Fraction = Percent / 100
Step 2: Reduce by dividing top and bottom by their GCD
Decimal = Percent / 100
(GCD = greatest common divisor)
Every percent is parts per hundred, so it begins as a fraction over 100. Dividing the numerator and denominator by their greatest common divisor leaves the fraction in lowest terms with no shared factor remaining.
Worked example
Convert 75 percent to a fraction in lowest terms.
- Write over 100: 75 / 100
- Greatest common divisor of 75 and 100 is 25
- Divide both: 75 / 25 = 3 and 100 / 25 = 4
- Reduced fraction = 3/4 (decimal 0.75)
75 percent equals 3/4. These are the calculator's default inputs, so the result above matches the widget exactly.
Common percentages as fractions
A quick reference for percentages you meet often.
| Percent | Decimal | Fraction |
|---|---|---|
| 25% | 0.25 | 1/4 |
| 50% | 0.50 | 1/2 |
| 75% | 0.75 | 3/4 |
| 12.5% | 0.125 | 1/8 |
| 150% | 1.50 | 3/2 |
Measurement and number standards: US National Institute of Standards and Technology (NIST).
Percent to fraction calculator: frequently asked questions
How do I convert a percent to a fraction?
Write the percent as a fraction over 100, then reduce it to lowest terms by dividing the top and bottom by their greatest common divisor. For 75 percent, write 75/100, then divide both by 25 to get 3/4. The starting denominator is always 100 because percent means parts per hundred.
How does the calculator reduce the fraction?
It finds the greatest common divisor (GCD) of the numerator and 100, then divides both by it. The GCD is the largest whole number that divides both exactly, so dividing by it leaves no further common factor, which is the definition of lowest terms. For 75/100 the GCD is 25, giving 3/4.
What about decimal percentages?
For a percent with decimals, such as 12.5 percent, first remove the decimal by scaling both numbers. 12.5/100 becomes 125/1000 by multiplying top and bottom by 10, which reduces to 1/8. The calculator handles a decimal percent by scaling to whole numbers before reducing.
Can a percent over 100 be a fraction?
Yes. A percent above 100 gives an improper fraction or a mixed number. For example 150 percent is 150/100, which reduces to 3/2, or one and a half. The same over-100 method applies; the result is simply greater than one.
What is the percent to fraction method?
Fraction equals the percent over 100, reduced by dividing the numerator and denominator by their greatest common divisor. The decimal form equals the percent divided by 100.
Official sources
- Measurement, units and number standards: US National Institute of Standards and Technology (NIST). As at 25 June 2026.
Reviewed by the CalculatorHub team, edited by James Graham, 25 June 2026. See our methodology. This is general information, not financial, tax, legal or investment advice.