Caffeine Calculator

Count the drinks and this adds up the caffeine in them, then measures the total against the 400 mg a day the FDA quotes for healthy adults. Enter cups of brewed or instant coffee, espresso shots, black or green tea, cola and energy drinks, plus the milligrams of anything else off a label, and it returns the total, the share of the guidance, the headroom left and which drink is carrying it. A second action takes one dose and decays it at a half-life you can set, so you can see what is still in circulation at bedtime and when it drops below the level that keeps you awake. The 400 mg figure is for healthy adults; pregnancy and adolescence carry much lower numbers, and the per-drink values are averages that real products stray a long way from.