Decimal to Fraction Calculator

Count the digits after the decimal point. Place the decimal value over the matching power of 10 (one digit goes over 10, two over 100, three over 1000, and so on). Then simplify the fraction by dividing numerator and denominator by their greatest common divisor. For 0.75 with two decimal places: 75/100 = 3/4.

Repeating decimals need a different method, usually setting up an equation: let x = 0.333…, then 10x = 3.333…, so 10x − x = 3, giving x = 3/9 = 1/3. This calculator handles terminating decimals only. If a repeating decimal is entered the result reflects whatever digits you typed (which is a finite, slightly different number).

The sign attaches to the numerator. For -0.4 the unsimplified fraction is -4/10, which simplifies to -2/5. The denominator is always positive.

When the decimal is greater than 1, the simplified fraction is improper (numerator larger than denominator). The mixed-number row shows the equivalent whole-number-plus-fraction form. For 1.25, the fraction is 5/4 and the mixed number is 1 1/4.

For terminating decimals it is exact: 0.75 returns 3/4, and 0.125 returns 1/8. JavaScript loses precision for numbers with very many decimal places (typically beyond 15 significant digits), so very long inputs can round slightly. Stick to inputs you would normally write out by hand.

Closely related. To convert a percent to a fraction, drop the percent sign and divide by 100, then convert that decimal to a fraction. For 75%, divide by 100 to get 0.75, which the calculator returns as 3/4. The percent row in the result shows the same value with a percent sign for cross-checking.