The numbers, per typical serving
Here is the caffeine content people are usually shocked by, per common serving:
• Espresso: ~63 mg per single shot (about 1 oz). A double shot is ~126 mg.
• Drip / brewed coffee: ~95 mg per 8 oz cup — and a 16 oz travel mug is closer to 190 mg.
• Cold brew: 150–240 mg per 16 oz — often the most caffeinated drink on the menu.
• Decaf: 2–7 mg per cup — low, but not zero.
The headline surprise: a shot of espresso has less caffeine than a regular cup of coffee. Espresso only tastes stronger because it is concentrated into a tiny volume. Add up any combination of drinks with the Caffeine Calculator.
Why espresso has less caffeine than drip
Espresso is *concentrated*, not *high-caffeine*. Its intensity comes from packing a lot of dissolved coffee into ~1 ounce of liquid. But a single shot uses only 7–9 g of coffee and about an ounce of water, so the total caffeine — around 63 mg — is modest.
A cup of drip coffee uses far more coffee and much more water: roughly 10–15 g of grounds brewed into 8–12 oz. More coffee plus a longer contact time with hot water means more total caffeine extracted, even though each sip tastes milder.
So "strong" is about concentration and flavor, while total caffeine depends on how much coffee and water you used — the brew ratio again. It is the same reason a big drip refill delivers more caffeine than a quick espresso.
Why cold brew is usually the most caffeinated
Cold brew tops the chart for two reasons. First, its brew ratio is high — often 1:5 to 1:8 coffee-to-water, far more coffee per cup than drip. Second, it steeps for 12–24 hours, and that long contact time extracts a large amount of caffeine even without heat.
The catch is dilution. Most cold brew is served as a concentrate cut with water or milk, which lowers the caffeine in the final glass. Undiluted concentrate can exceed 240 mg per cup; a well-diluted ready-to-drink cold brew lands closer to drip. Always check whether a number refers to concentrate or the poured drink. Learn the method in how to make cold brew at home.
How much is too much?
The FDA cites 400 mg of caffeine per day as an amount not generally associated with negative effects for healthy adults — roughly four 8 oz cups of drip, or two large cold brews. Pregnant people are usually advised to stay under 200 mg; talk to your doctor.
Timing matters as much as total dose. Caffeine has a half-life of about 5–6 hours, so an afternoon coffee can still affect sleep. See caffeine and sleep and use the Caffeine Half-Life Calculator to see how much is left in your system before bed.