It would take 500w of power to double the loudness of a 50w amp, all other things being relatively equal. So a 100w amp is about 12% louder than a 50w amp. Of

It would take 500w of power to double the loudness of a 50w amp, all other things being relatively equal. So a 100w amp is about 12% louder than a 50w amp. Of course this means you have more headroom with 100w. But it’s also why a lot of guitar players prefer 50w as you can get to an overdriven tone without being as loud. And why in studio environments, 15w-25w amps are adored as you can push them to get overdrive but not be as loud as a 50w or 100w - but still pretty loud.