Thus the need for a little math. KWH used in a month will indeed convert to AVERAGE amps required on a daily (or hourly) basis. And yeah, you'd have to allow extra for startup amps, but most generators will start a lot more than they will run for extended periods. Hence the statement "general idea," rather than "exactly." FWIW... my bill (on a Coop) actually shows daily usage, so I could just pick the highest day in the highest month and get a "pretty close" hourly average.