The caffeine in coffee varies by brew method , an 8 oz drip cup has 80 to 120mg, an espresso shot has 60 to 75mg, and cold brew concentrate can hit 200mg or more. The FDA recommends 400mg per day as the guideline for healthy adults. This guide covers how much caffeine is in each brew method, why light roast has slightly more than dark, how caffeine affects the body, and what to know about kids and caffeine.