Convert a fraction into a decimal and a percentage by dividing the numerator by the denominator.
Calculations happen locally. We do not send your values to our server.
1/8 becomes 0.125, which is 12.5%, and 5/16 becomes 0.3125, or 31.25%. An improper fraction such as 7/4 gives 1.75 or 175%, while −3/5 gives −0.6 and −60%.
The numerator is divided by the denominator to get the decimal, and that decimal is multiplied by 100 for the percentage, so both lines always describe the same value. A denominator of 0 is rejected because division by zero has no value, and a minus sign on either number makes the result negative.
Some fractions never end in decimal form. 2/3 is 0.666… repeating forever, so the display rounds it to 0.66666667 and the percentage to 66.66666667%. Only fractions whose reduced denominator has no prime factors other than 2 and 5 produce a terminating decimal, which is why 1/8 ends but 1/3 does not.
Enter the top number as the numerator and the bottom number as the denominator. 1/8 becomes 0.125, which is 12.5%, and 5/16 becomes 0.3125, or 31.25%. These fractions are common on rulers, drill bits and recipe cards, where parts of an inch or cup need a decimal for a calculator or spreadsheet. The percentage is simply the decimal multiplied by 100, so both lines always describe the same value.
A numerator larger than the denominator produces a value above 1: 7/4 is 1.75, or 175%. A minus sign on either number makes the result negative, so −3/5 is −0.6 and −60%. Some fractions never end in decimal form. 2/3 is 0.666… with the 6 repeating forever, so the display shows 0.66666667 after rounding the last digit. Only fractions whose reduced denominator has no prime factors other than 2 and 5 give a terminating decimal, which is why 1/8 ends but 1/3 does not.
A rounded decimal is not always interchangeable with the exact fraction. Three thirds make exactly 1, but 0.33333333 × 3 is 0.99999999, so rounded decimals can leave a small gap when they are added up in a spreadsheet. Keep the fraction for exact work and round the decimal only at the final step to the precision you need, for example two decimal places for money. To convert in the other direction, use the Decimal to Fraction tool. A denominator of zero is rejected because division by zero has no value.
| Input | Result |
|---|---|
1/8 | 0.125 · 12.5% |
5/16 | 0.3125 · 31.25% |
7/4 | 1.75 · 175% |
-3/5 | -0.6 · -60% |
2/3 | 0.66666667 · 66.66666667% |
Yes. An improper fraction simply gives a value above 1: 7/4 is 1.75, or 175%. Percentages above 100% are perfectly valid and mean the part is larger than the whole it is compared with, such as a price that has grown beyond its original value.
The display uses a limited number of digits, so 2/3 appears as 0.66666667 with the last digit rounded up. The calculation itself keeps normal floating-point precision. When you need an exact value, keep the fraction and round only at the final step.
Whenever the total must come out exactly. Three thirds make exactly 1, but 0.33333333 added three times gives 0.99999999, so rounded decimals can leave a small gap in a spreadsheet. Use the Decimal to Fraction tool to convert back the other way.
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