About this tool
Turn a decimal into an exact, fully-reduced fraction and its mixed-number form, or switch modes to convert a fraction back into a decimal — all in your browser. Type 0.375 and you get 3/8; type a repeating value and you get its true fraction, for example 0.333… → 1/3.
Terminating decimals are exact: the digits become the numerator over a power of ten (0.375 = 375/1000), then the fraction is divided by the greatest common divisor to reach lowest terms (3/8). Repeating decimals are handled algebraically rather than by guessing — end the number with … (three dots) to repeat the final digit, so 0.1666… becomes 1/6, or state the repeating block explicitly in parentheses like 0.1(6) or 0.(3) for multi-digit repetends. Whole-number arithmetic uses big integers, so even long decimals reduce without rounding error.
In Fraction → Decimal mode, enter a simple fraction such as 3/8 or a mixed number like 1 1/2 to see the decimal value and its percentage. This complements the reverse Fraction to Decimal converter and is handy for schoolwork, tape-measure and drill-bit sizes, and any time you need an exact ratio instead of a rounded number.