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Fraction to Percent Converter

Convert fractions to percentages and percentages back to simplified fractions, with the decimal form as the bridge and every step shown along the way.

Mehmet Demiray Published Updated
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Percentage Calculator: one tool for every percent questionCalculate percentages, changes, differences, errors and averages here, then jump to the specialized tool for each question.
The top number of the fraction
The bottom number of the fraction

The decimal is the bridge: fraction → divide → decimal → ×100 → percent.

Fractions are simplified by dividing both parts by their greatest common divisor.

Worth memorizing: 1/2 = 50%, 1/4 = 25%, 1/5 = 20%, 1/8 = 12.5%.

Three Faces of the Same Number

A fraction, a decimal and a percent are three notations for one value. The fraction 34\frac{3}{4}, the decimal 0.75 and 75% all describe exactly the same quantity, and the decimal sits in the middle as the bridge: divide the fraction to reach it, multiply by 100 to reach the percent. Each notation has a natural home. Fractions dominate recipes, measurements and probability, where quantities split into neat parts. Decimals rule calculators and spreadsheets, because arithmetic on them is direct. Percents win whenever people compare or communicate, since a base of 100 makes 75% instantly meaningful in a way 1824\frac{18}{24} is not, even though the two are equal. This converter moves in both directions on one page and shows the decimal at every step, so the relationship stays visible instead of hiding inside a memorized rule.

Fraction to Percent, Step by Step

The conversion is two operations: divide the numerator by the denominator, then multiply by 100. ab=(ab×100)%\frac{a}{b} = \left(\frac{a}{b} \times 100\right)\% For 34\frac{3}{4}, dividing 3 by 4 gives 0.75, and multiplying by 100 gives 75%. For 78\frac{7}{8}, the decimal is 0.875 and the percent is 87.5%. Some fractions refuse to terminate: 13\frac{1}{3} produces a repeating decimal, so its percent form repeats too, and the honest way to write it is 33.33% with a note that the digits continue, usually rounded to 33.3% in schoolwork. The converter flags repeating results explicitly rather than pretending the number stops, and it keeps the decimal form on screen so you can see which of the two steps introduced any rounding.

Percent to Fraction, Step by Step

Going the other way, write the percentage over 100 and simplify by the greatest common divisor, following P%=P100P\% = \frac{P}{100}. Starting from 40%, the raw fraction is 40100\frac{40}{100}; the GCD of the two numbers is 20, and dividing both by it leaves 25\frac{2}{5}. Decimals in the percentage need one extra move: 62.5% becomes 62.5100\frac{62.5}{100}, which scales to 6251000\frac{625}{1000} to clear the decimal, and a GCD of 125 reduces it to 58\frac{5}{8}. Percentages above 100 work identically, so 150% simplifies to 32\frac{3}{2}, often spoken as one and a half. The converter shows the unsimplified fraction as an intermediate step before reducing it, which is exactly the working a teacher expects to see, and it reports the divisor it used so you can verify the reduction yourself.

The Conversions Worth Memorizing

A handful of conversions appear so often that recognizing them on sight is faster than any calculation. The families worth knowing are the halves, quarters, fifths and eighths, which all terminate cleanly, plus the thirds, which repeat.

Fraction Decimal Percent
12\frac{1}{2} 0.5 50%
14\frac{1}{4} 0.25 25%
34\frac{3}{4} 0.75 75%
15\frac{1}{5} 0.2 20%
18\frac{1}{8} 0.125 12.5%
13\frac{1}{3} about 0.333 about 33.3%
23\frac{2}{3} about 0.667 about 66.7%

Once these anchors are memorized, nearby values come along free: if 18\frac{1}{8} is 12.5%, then 38\frac{3}{8} is three times that, 37.5%, with no long division required.

Where These Conversions Appear

Test scores are the classic case: 48 correct out of 60 questions is the fraction 4860\frac{48}{60}, which reduces to 45\frac{4}{5} and converts to 80%, the number that actually goes on the report; the marks percentage calculator automates exactly this for full exams. Shopping runs in the reverse direction, since a sign offering 25% off is telling you a quarter comes off the price, and the discount calculator turns that into money saved. Recipe scaling lives in fractions, because making three quarters of a batch means multiplying every ingredient by 0.75. Probability statements switch notation constantly, with a 14\frac{1}{4} chance, 0.25 and 25% all naming the same likelihood. Whenever a task needs the percentage of a specific amount rather than a pure conversion, the general percentage calculator picks up where this one stops.

The ones we answer the most.

How do I turn a fraction into a percentage?

Divide the numerator by the denominator, then multiply the result by 100. For 3/4, the division gives 0.75 and multiplying by 100 gives 75%. The decimal step is worth keeping visible, because it is the bridge between the two notations and the place where any rounding happens.

How do I turn a percentage into a fraction in lowest terms?

Write the percentage over 100, then divide the top and bottom by their greatest common divisor. From 40% you get 40/100, and dividing both by the GCD of 20 leaves 2/5. If the percentage has decimals, first multiply both parts to clear them, so 62.5% becomes 625/1,000 and reduces to 5/8.

What connects fractions, decimals and percents?

They are three notations for the same value, linked through the decimal form. Dividing a fraction produces its decimal, and multiplying that decimal by 100 produces the percent, so 7/8, 0.875 and 87.5% are one number written three ways. Converting between any pair is just moving along this chain in one direction or the other.

What happens with fractions that give repeating decimals?

The percentage repeats as well, so it can only be written approximately. Dividing 1 by 3 gives a decimal whose digits never end, and the percent form is usually rounded to 33.3% or 33.33% depending on the precision needed. The converter flags these cases and states the rounding, rather than presenting a truncated value as exact.

References

  1. Fraction · Wikipedia
  2. Greatest common divisor · Wikipedia