HesapHanem

Decimal to Fraction Converter

Turn any decimal into its simplest fraction.

How it is calculated

The tool counts the digits after the decimal point, d, and writes the number over 10d: the numerator is the value × 10d and the denominator is 10d. It then finds the greatest common divisor (GCD) with Euclid's algorithm and divides both parts by it, giving the lowest terms. A whole number comes back without a denominator, and the sign is kept in front. The input is read as the text you type, so only finite decimals work. Scientific notation is accepted (1e-5 gives 1/100000), and more than 15 decimals are rounded to 15. A repeating decimal such as 0.3333 gives 3333/10000, not 1/3, because the tool cannot know the digits repeat.

Worked example

Convert 0.375. There are 3 digits after the point, so the denominator is 103 = 1,000 and the numerator is 0.375 × 1,000 = 375, giving 375/1000. The GCD of 375 and 1000 is 125. Dividing both by 125 gives 3 and 8. The result is 3/8.

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Common mistakes

  • Typing 0.333 and expecting 1/3. The tool converts exactly what is written, giving 333/1000. Repeating decimals need the fraction typed another way.
  • Using a decimal comma such as 0,375. The input expects a decimal point.
  • Entering a rounded value and expecting the original fraction. 0.50 and 0.5 both reduce to 1/2, but 0.67 gives 67/100, not 2/3.
  • Reading a fraction larger than 1 as wrong. 2.5 gives 5/2, an improper fraction, not 2 1/2.

About this calculator

This tool converts a decimal number into a fraction reduced to its simplest form — for example, turning 0.75 into 3/4 rather than leaving it as an unwieldy fraction over a power of ten — by finding the greatest common divisor between the numerator and denominator.

It is used by students and teachers working through math homework that requires fraction answers, by woodworkers and machinists converting a decimal measurement from a digital caliper into the nearest fraction of an inch used on a tape measure or drill bit set, and by cooks scaling a recipe that lists decimal quantities into more kitchen-friendly fractions.

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Comments (1)

  • Editorial team

    The tool gives the exact fraction of what you type, not the nearest ruler mark. A caliper reading of 0.31 inch becomes 31/100, which no tape measure shows. To get a usable fraction, multiply the reading by 16, round to a whole number, and put that over 16: 0.31 times 16 is 4.96, so 5/16, which the tool then confirms as 0.3125. What precision do you need, sixteenths, thirty-seconds or finer?

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