Decimal to Fraction Calculator

Get the exact fraction for a decimal, or set a maximum denominator to find the closest practical fraction — handy for tape measures and recipes.

Convert a decimal

Leave blank for the exact fraction. Use 16 for the nearest sixteenth.

Fraction5/8

Working

  1. Write the decimal over 1,000: 625/1000
  2. Divide top and bottom by their greatest common factor, 125: 5/8

How it works

A terminating decimal is a fraction over a power of ten: 0.625 = 625/1000. Dividing top and bottom by their greatest common factor (125) gives 5/8.

decimal with k digits after the point = digits / 10k, then simplify

When you set a maximum denominator, the calculator uses continued fractions to find the closest fraction whose denominator does not exceed your limit, and tells you how far it is from the decimal you entered.

Worked example

Convert 0.625

  1. 0.625 has three decimal places, so write it as 625/1000
  2. GCF(625, 1000) = 125
  3. 625 ÷ 125 = 5 and 1000 ÷ 125 = 8

0.625 = 5/8

Practical uses

  • Converting a decimal inch reading (e.g. 0.3125 in) to a tape-measure fraction (5/16 in).
  • Scaling recipes that use fractional cups or spoons.
  • Recognising well-known values: 0.1428571… is close to 1/7.