text: how much electricty makes how much hydrogen? i know that the amount (amps) of electricity determines the amount of hydrogen (and oxygen) produced in electrolsis, but how much to make how much? and over what period of time? if you look at the half reactions taking place within an electrolytic cell,  cathode, reduction: 2 h2o (l) + 2 electrons --> h2 (g) + 2 oh- (aq)  anode, oxidation, 2 h2o (l) --> 4 h+ (aq) + o2 (g) + 4 electrons  so you can see tha for every 2 moles of electrons (aka, 2 faradays of charge), 1 mole of hydrogen gas is produced. 1 faraday of charge = about 96485 coulombs of charge.  a current of 1 amp means that every second, 1 coulomb of charge is flowing into (and out of) your cell. 1 amp = 1 c / s   you can take this and do the conversions yourself to taylor it your specific conditions and in what units you want to use.