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Fraction to Percent Calculator
To turn a fraction into a percent, divide the top by the bottom and multiply by 100: 3/8 is 0.375, so 37.5%. When the bottom divides into 100, scale it instead: 17/20 is 85/100, which is 85%. Thirds and sevenths never end, so 2/3 is about 66.67%. This calculator shows the steps.
Divide, then multiply by 100.
- 100 ÷ 20 = 5, so multiply the top and bottom by 5: 17/20 = 85/100.
- 85 out of 100 is 85%.
| Result | Value |
|---|---|
| Percent | 85% |
| Decimal | 0.85 |
| Lowest terms | 17/20 |
| Out of 100 | 85 out of 100 |
The figure above is an example (17 marks out of 20): put in your own. Type 3/8, a mixed number such as 1 1/4, or a count such as 17 out of 20. For a whole tally of several categories, the tally percentage calculator makes the percentages add to 100. Worked out exactly in this browser and kept there; nothing is sent anywhere.
Type a fraction, a mixed number or a score such as 17 out of 20, and read the percent with its working. Fractions that repeat are shown exactly and rounded to the places you choose.
Converting a fraction to a percent writes it as a number of hundredths: the fraction’s value multiplied by 100. 17/20 is 85 hundredths, 85%.
- No sign-up
- Nothing uploaded
- Shows every step
- Works offline
- Exact, no rounding errors
Key facts
| Detail | Answer |
|---|---|
| Rule | Top ÷ bottom × 100 |
| Example | 17/20 = 85/100 = 85% |
| Repeating | 2/3 = 66.(6)%, about 66.67% |
| Accepts | 3/8, 1 1/4, 17 out of 20, 17 of 20 |
| Refuses | A denominator of 0 |
| Where your numbers are kept | This browser only |
How to convert a fraction to a percent
Scale to 100 if you can; otherwise divide.
Check the denominator
If it divides 100 (2, 4, 5, 10, 20, 25, 50), scale up.
Scale to hundredths
17/20: multiply top and bottom by 5 to get 85/100.
Or divide
3 ÷ 8 = 0.375.
Multiply by 100
0.375 becomes 37.5%.
Round if it repeats
2/3 is 66.(6)%; to two places, 66.67%.
Who converts fractions to percents
Anyone with a score, a share or a count over a total.
Students and teachers
A test mark out of any total as a percent.
Coaches
Shots on target, free throws made, passes completed.
Survey takers
A count of answers over the number asked.
Cooks
3/4 of a cup as 75% of the recipe.
Pupils doing homework
Fraction to percent with the method shown.
Anyone reading odds
1 in 8 as 12.5%.
Scale to 100 or divide: two ways to the same percent
There are two ways to turn a fraction into a percent, and the calculator uses whichever is shorter. When the denominator divides into 100, scale the fraction up to hundredths and read the percent straight off the top. Otherwise, divide the top by the bottom and multiply by 100.
| Fraction | Method | Percent |
|---|---|---|
| 17/20 | × 5 → 85/100 | 85% |
| 3/4 | × 25 → 75/100 | 75% |
| 7/25 | × 4 → 28/100 | 28% |
| 9/50 | × 2 → 18/100 | 18% |
| 3/8 | 8 does not divide 100: 3 ÷ 8 = 0.375 | 37.5% |
| 2/3 | 2 ÷ 3 = 0.(6) | 66.(6)%, about 66.67% |
Scaling works for the denominators 1, 2, 4, 5, 10, 20, 25, 50 and 100, the divisors of 100, and gives a whole percent every time. Dividing works for everything. It is the Grade 6 idea of a percent as a rate per 100 (Common Core 6.RP.A.3c): 17/20 and 85/100 are the same rate, and the second is the one that names the percent.
Test scores as percentages
The commonest fraction-to-percent conversion is a mark: a score out of a total. These tables cover the usual totals; the calculator does any total, including “43 out of 57” typed just like that.
| Marks out of | Score | Score | Score | Score |
|---|---|---|---|---|
| 20 | 16 = 80% | 17 = 85% | 18 = 90% | 19 = 95% |
| 25 | 20 = 80% | 21 = 84% | 22 = 88% | 23 = 92% |
| 30 | 24 = 80% | 25 = 83.33% | 26 = 86.67% | 27 = 90% |
| 40 | 32 = 80% | 34 = 85% | 36 = 90% | 38 = 95% |
| 50 | 40 = 80% | 42 = 84% | 45 = 90% | 48 = 96% |
| 60 | 48 = 80% | 51 = 85% | 54 = 90% | 57 = 95% |
Totals with a prime factor other than 2 and 5 (30, 60, 70) can give percents that repeat: 25 out of 30 is 83.(3)%, though 24 out of 30 is exactly 80%. Totals made only of 2s and 5s, such as 40 or 80, always end, even when they do not divide 100: 34 out of 40 is 85% and 3 out of 8 is 37.5%. Marking schemes usually say how to round; if not, two decimal places and the rule “half rounds up” is the convention. Combining marks from two papers with different totals is not an average of the two percents: add the marks and the totals first, as the average calculator explains.
Thirds, sixths and sevenths: percents that never end
A fraction makes a percent that ends only when its denominator, in lowest terms, has no prime factors other than 2 and 5, the same rule as for decimals. Thirds, sixths, sevenths, ninths and twelfths never come out exactly, which is why their percents are always quoted rounded.
| Fraction | Exact percent | 2 places | Whole percent |
|---|---|---|---|
| 1/3 | 33.(3)% | 33.33% | 33% |
| 2/3 | 66.(6)% | 66.67% | 67% |
| 1/6 | 16.(6)% | 16.67% | 17% |
| 1/7 | 14.(285714)% | 14.29% | 14% |
| 1/9 | 11.(1)% | 11.11% | 11% |
| 1/12 | 8.(3)% | 8.33% | 8% |
| 1/8 | 12.5% | 12.5% | 13% (12.5 rounds up) |
The decimal form of every fraction either ends or repeats, a fact the Common Core asks pupils to know by Grade 7 (7.NS.A.2d). The calculator shows the repeating block in brackets beside the rounded figure, so 2/3 is never confused with 66.67/100. For the long division behind it, see the fraction to decimal calculator.
What this calculator does not do
One fraction in, one percent out. The calculator converts a single fraction, mixed number or count. It does not add fractions (the fraction calculator does), and it does not split a tally into percentages that add to 100 (the tally percentage calculator handles the rounding that needs). A denominator of 0 is refused. Decimals are refused with a pointer to the decimal to percent converter, so 0.5 is never read as a fraction by mistake.
This calculator or an answer-only one
What this page does that a typical answer-only widget does not.
| This page | A typical calculator | |
|---|---|---|
| Scores typed naturally | 17 out of 20 accepted | Two boxes, numbers only |
| Mixed numbers | 1 1/4 accepted | Often not |
| Repeating percents | 66.(6)% and 66.67% | 66.66666667% |
| Shows the method | Scale or divide, named | Answer only |
| Exact arithmetic | No floating-point drift | Floating point |
| Your numbers leave the browser | Never | Varies |
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Frequently asked questions
How do you convert a fraction to a percent?
Divide the numerator by the denominator and multiply by 100. 3/8 is 3 ÷ 8 = 0.375, which is 37.5%. If the denominator divides into 100, you can scale instead: 17/20 is 85/100, so 85%. Both methods always give the same answer.
What is 2/3 as a percent?
66.(6)%, with the 6 repeating for ever, usually rounded to 66.67% or 67%. Thirds never make an exact percent because 3 does not divide into any power of 10. 1/3 is 33.(3)%, about 33.33%. The same goes for any denominator with a factor of 3 or 7.
How do I work out my test score as a percentage?
Divide your mark by the total and multiply by 100. 17 out of 20 is 0.85, so 85%; 43 out of 57 is about 75.44%. Type the score as “43 out of 57” into the calculator and it does the rest, showing whether the percent is exact.
What is 1/8 as a percent?
12.5%. One eighth is 0.125, and 0.125 × 100 = 12.5. The other eighths follow in steps of 12.5: 3/8 is 37.5%, 5/8 is 62.5% and 7/8 is 87.5%. Eighths end because 8 is 2 × 2 × 2. A quarter, 2/8, is 25%.
How do you convert a mixed number to a percent?
Turn it into an improper fraction or a decimal first. 1 1/4 is 5/4, which is 1.25, so 125%. A mixed number is always more than 100%, because the whole number part alone is at least 100%. 2 1/2 is 250% in the same way.
Why do some fractions not give an exact percent?
A fraction in lowest terms gives an exact percent only if its denominator has no prime factors other than 2 and 5. 1/6 has a factor of 3, so it is 16.(6)%. The calculator marks the repeating digits in brackets and rounds them for display.
How do I add up percentages from several fractions?
If the fractions share a total, add the tops first: 3 of 20 and 5 of 20 is 8 of 20, 40%. If the totals differ, add the counts and the totals, then divide once; adding or averaging the separate percents gives the wrong answer.
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