Among other things, it depends upon the temperature at which you fermented (meaning what actual temperature did your wort experience, which is different from the air temperature by up to 5 degrees), and it depends upon what kind of sugar you are talking about. It also appreciably depends upon your answer as to how many "volumes of CO2" you are shooting for with respect to your carbonation level. This generally ranges from 2.2 to 2.7.
The reason why the fermentation temperature is needed is that your ale likely has roughly between 0.8 and 1.1 volumes of CO2 already dissolved in it, and this is temperature history dependent. You are not carbonating from flat to 2.2 to 2.7 volumes, you are rather carbonating from already somewhat carbonated to 2.2 to 2.7 volumes.