If you have MS Excel either on your phone or PC it easily converts fractions to decimals and back.
For example, format cell A1 as a fraction and enter 15/16. Put =A1 in cell B1 and voila it gives you the decimal equivalent, 0.9375 (rounded to 4 decimals places – more if you want).
You can work the other way by formatting A2 as a fraction and entering the formula =B2. Any decimal you then enter in B2 is converted to a fraction. You can also specify how the spreadsheet will convert decimals that are not an exact equivalent to a fraction to the nearest 1/4, 1/10, 1/16, etc up to 3 digits 1/999.