Converting fractions to percentages is a fundamental math skill used in cooking, grading, statistics, and everyday problem-solving. A fraction like 3/4 and a percentage like 75% express the same value — the conversion simply scales the fraction so the denominator becomes 100.
The conversion formula
Divide the top number (numerator) by the bottom number (denominator) to get a decimal, then multiply by 100 to convert to a percentage. For 3/8: 3 ÷ 8 = 0.375, then 0.375 × 100 = 37.5%.
Common fractions and their percentages
| Fraction | Decimal | Percentage |
|---|---|---|
| 1/2 | 0.5 | 50% |
| 1/3 | 0.333... | 33.33% |
| 2/3 | 0.666... | 66.67% |
| 1/4 | 0.25 | 25% |
| 3/4 | 0.75 | 75% |
| 1/5 | 0.2 | 20% |
| 1/8 | 0.125 | 12.5% |
| 3/8 | 0.375 | 37.5% |
| 1/10 | 0.1 | 10% |
Mixed numbers
A mixed number combines a whole number with a fraction, like 2¾. To convert it, first turn it into an improper fraction: 2¾ = (2 × 4 + 3) ÷ 4 = 11/4. Then apply the formula: 11 ÷ 4 × 100 = 275%. Any mixed number will always be greater than 100% because the whole-number part alone is at least one full unit.
Repeating decimals
Some fractions produce repeating decimals when converted. 1/3 = 0.333... (repeating), which is 33.33...%. In practice, these are rounded to a reasonable number of decimal places. The repeating pattern doesn't affect accuracy for most everyday uses — 33.33% is precise enough for nearly all calculations.
Where you'll use this
- Recipes: Scaling recipes that use fractional measurements (¾ cup, ⅓ teaspoon) to percentages of total volume.
- School: Converting test scores expressed as fractions (42/50) into percentage grades.
- Construction: Converting fractional inch measurements to percentage-based tolerances.
- Statistics: Expressing survey results like "3 out of 5 respondents" as a cleaner "60%."