Caffeine Calculator

A standard 8-ounce cup of drip coffee contains 80-100mg of caffeine. A 12-ounce serving (a typical "small" at most cafes) contains 120-150mg. The exact amount depends on the bean variety, roast level, grind size, and brew method. Robusta beans contain nearly double the caffeine of Arabica, and cold brew concentrate can reach 200mg per 8 ounces.

The FDA sets the safe daily limit at 400mg of caffeine for healthy adults, which is roughly four 8-ounce cups of drip coffee. Consuming more than 400mg can cause anxiety, insomnia, rapid heartbeat, and digestive issues. Pregnant individuals are advised to stay under 200mg per day. Individual tolerance varies widely based on genetics, body weight, and habitual consumption.

Dark roast and light roast contain nearly identical amounts of caffeine per gram of coffee. The roasting process destroys less than 5% of the caffeine molecule, which is remarkably heat-stable. The misconception exists because dark roast tastes bolder. If you measure by scoop rather than weight, light roast actually has slightly more caffeine because the beans are denser and heavier.

Drip coffee has more total caffeine per serving. A single espresso shot contains 63mg of caffeine in 1 ounce, while an 8-ounce drip coffee contains 80-100mg. Espresso is more concentrated per ounce, but you drink far less of it. A standard double espresso (2 oz, 126mg) still has less caffeine than a 12-ounce drip coffee (120-150mg).

Caffeine has a half-life of approximately 5 hours in most adults. This means if you consume 200mg at noon, you still have 100mg active in your system at 5 PM and 50mg at 10 PM. Full elimination takes 10-12 hours. Sleep researchers recommend cutting off caffeine intake 8-10 hours before bedtime. Genetics, liver function, and medications can significantly alter this timeline.

Cold brew concentrate contains significantly more caffeine than regular drip coffee, typically 150-200mg per 8 ounces compared to 80-100mg for drip. The long steeping time (12-24 hours) and high coffee-to-water ratio extract more caffeine. However, most cold brew is diluted 1:1 with water or milk before serving, which brings the caffeine content closer to standard drip levels.