Decimal to Fraction

The Decimal to Fraction tool converts a decimal number into its exact fractional equivalent, expressed in lowest terms. You type a value such as 0.75 or 2.625 and it returns the fraction — 3/4 or 21/8 in those examples — along with any whole-number part. This is the inverse of dividing a numerator by a denominator, and it is useful whenever a decimal needs to be expressed in the cleaner, exact form that fractions provide.

For a terminating decimal, the conversion works by placing the digits after the decimal point over the appropriate power of ten: 0.75 becomes 75/100, which then reduces by the greatest common factor to 3/4. For repeating decimals the math is different — a repeating block like 0.333... is handled with an algebraic trick that subtracts shifted copies of the number to eliminate the repetition, yielding 1/3. The final answer is always simplified by dividing top and bottom by their greatest common factor.

Typical uses include translating measurements from a digital readout back into the inch-and-fraction markings on a tape measure, expressing probabilities or interest rates as exact ratios, and preparing answers for math classes that demand fractional form. Engineers and machinists rely on it to move between decimal CAD dimensions and fractional stock sizes.

A useful tip is to recognize that many decimals you encounter are rounded approximations, so 0.333 (three digits) is not exactly 1/3 — decide whether you want the literal terminating fraction (333/1000) or the intended repeating value. For converting the other direction, the Fractions Calculator and a simple division give you the decimal back, and the GCF & LCM Calculator can confirm the reduction step.