confused by what your asking? it should just already tell you what the % gain/loss is with your broker or if you use STT or ToS. or use yahoo finance or if your trading otc market use https://www.otcmarkets.com/market-activity/current-otc-market

@Clean_Supreme I ment when you look at stock on the chart how do you do the math quickly like tim does to say its 50% down or up on the day, he says it on video tutorials really quickly and im thinking how does he do the math so quickly

@gmuni it should just say it on the chart or through your broker like with etrade it live streams the % changes as im watching it....no math needed