The short answer: a range, not one number
If you want one figure for how much caffeine is in a cup of coffee, the honest answer is a range. USDA FoodData Central lists brewed coffee at about 40 mg per 100 g, which is roughly 12 mg per fluid ounce. The FDA's consumer page gives 113 to 247 mg for a 12 fl oz cup. Harvard's Nutrition Source puts a cup (8 oz) near 95 mg. We scale those published figures to the size you pick and show the whole spread.
Why so wide? Caffeine in the cup depends on the coffee itself, how it was roasted and ground, how long and how hot the water was in contact with it, and how much you pour. A mug at home and a paper cup from a shop are not the same drink, even when both are called "a coffee".
Caffeine by drink and size
This table uses only figures from USDA, the FDA and Harvard. Ranges are rounded outward so they still cover each source. Cold brew is left out on purpose: none of the three lists it, and we do not guess.
| Drink and size | Caffeine (mg) | Sources |
|---|---|---|
| Brewed (drip) coffee, 8 fl oz | 75–165 mg | USDA, FDA, Harvard |
| Brewed (drip) coffee, 12 fl oz | 110–250 mg | USDA, FDA, Harvard |
| Brewed (drip) coffee, 16 fl oz | 150–330 mg | USDA, FDA, Harvard |
| Instant coffee, 8 fl oz | 60–65 mg | USDA, Harvard |
| Decaf brewed coffee, 8 fl oz | 2–16 mg | USDA, FDA, Harvard |
| Espresso, 1 shot | 60–95 mg | USDA, Harvard |
| Espresso, 2 shots | 125–190 mg | USDA, Harvard |
Ranges, not exact numbers: caffeine varies with the bean, roast, grind, brew time and serving size. Cold brew is not listed by USDA, FDA or Harvard, so it is left out. Last checked 2026-11-04.
Per ounce versus per serving
Espresso is strong by the ounce and small by the serving. From the same sources, brewed coffee works out to about 9 to 21 mg per fluid ounce, while espresso is about 43 to 63 mg per fluid ounce. A single shot is only 1 to 1.5 fl oz, so one shot (about 63 to 95 mg) lands inside the range for an 8 fl oz cup of brewed coffee (about 75 to 165 mg), not above it.
That is why "does espresso have more caffeine than coffee?" has two honest answers: more per ounce, but usually less in the cup you actually drink. We go through the numbers in caffeine in an espresso shot.
What changes the caffeine in your cup
- Serving size. The biggest lever you control. A 16 fl oz cup is double an 8 fl oz one.
- How much coffee you use. A stronger ratio means more coffee per cup. See the coffee ratio calculator.
- Bean, roast, grind and brew time. All of them move the figure, and our sources do not give a single rule for any of them, so we do not either.
- Instant versus brewed. USDA and Harvard agree on about 60 mg per 8 fl oz for instant, a narrow range, but it depends on how much powder you stir in.
Add up your own day
One cup is easy; a day with a flat white, a refill and an afternoon espresso is not. The caffeine calculator lets you add several drinks and shows the total as a range against the FDA's 400 mg reference.