Its not a set percentage like that. You figure out what's the maximum money you want to lose on a trade, let's say 100 dollars. Then u find out where support is and you say "if it breaks this support level I'm cutting losses." Then, based on the support level and you planned entry price you do math to figure out how many shares u can buy.

TIM need a FIsical RULE, on RISK AND REWARD.. people need quickly check with out asking the brain to check old files.

I agree

there are a lot of spreadsheets out there that will help you manage risk. I have links to a few, DM if interested (can't post outside links on here due to incestuous knowledge rules)