How much caffeine is in a cup of coffee depends on the size of the cup, how strong it is brewed, and the beans. Here are the typical numbers by cup size and by drink, what makes them go up or down, and how much caffeine is considered too much.
Quick answer
About 96 mgThat is the caffeine in a typical 8-ounce cup of brewed coffee, according to Mayo Clinic. The FDA gives a range of about 80 to 100 mg for an 8-ounce cup. A 12-ounce mug is roughly 140 mg.
Caffeine by Cup Size
Caffeine scales with the amount of coffee in the cup. These estimates assume ordinary home-brewed drip coffee at about 96 mg per 8 ounces; stronger coffee-shop brews can run well above them.
| Cup size | Typical caffeine |
|---|---|
| 8 oz (1 cup) | about 96 mg |
| 12 oz (tall mug) | about 140 mg |
| 16 oz | about 190 mg |
| 20 oz | about 240 mg |
In grams, an 8-ounce cup holds about 0.1 g of caffeine (96 mg is 0.096 g).
Caffeine by Coffee Drink
Espresso has more caffeine per ounce than drip coffee, but a shot is small, so a single shot has less caffeine than a cup of drip. Milk drinks get their caffeine from the shots in them, so a latte, cappuccino or Americano with a double shot has about the same caffeine as a double espresso.
| Drink | Serving | Typical caffeine |
|---|---|---|
| Brewed (drip) coffee | 8 oz | 96 mg |
| Espresso, single shot | 1 oz | 64 mg |
| Espresso, double shot | 2 oz | about 128 mg |
| Latte, cappuccino or Americano (single shot) | any size | about 64 mg |
| Latte, cappuccino or Americano (double shot) | any size | about 128 mg |
| Instant coffee | 8 oz | 62 mg |
| Decaf brewed coffee | 8 oz | about 2 mg |
Figures for brewed, espresso, instant and decaf are from Mayo Clinic; milk drinks are based on the number of espresso shots. Real amounts vary with the beans and the recipe.
What Changes the Caffeine in Your Cup
Robusta beans have roughly twice the caffeine of Arabica, about 2.2 to 2.7 percent by weight versus 1.2 to 1.5 percent. Most specialty coffee is Arabica; cheaper blends and many instant coffees use Robusta. More in Arabica vs Robusta.
Roasting barely changes caffeine. Dark beans lose more water and weight, so gram for gram they hold about the same caffeine; measured by the scoop, light roast gives slightly more because the beans are denser. See our guide to roast levels.
The more coffee you use per cup of water, the more caffeine you get. A strong brew can easily double the numbers above. Our coffee brew calculator shows the ratio you are using.
Coffee-shop sizes are much bigger than an 8-ounce cup, and their brews are often stronger, so a large café coffee can contain several times the caffeine of a home cup.
Iced coffee made by pouring hot coffee over ice has a little less caffeine per glass, because the ice takes up space and dilutes it as it melts. Cold brew varies widely: it is usually made as a strong concentrate, so how much caffeine you get depends on how much you dilute it.
How Much Caffeine Is Too Much?
The FDA cites 400 mg a day for most healthy adults as an amount not generally linked to negative effects. That is about two to three 12-ounce cups of brewed coffee. People vary a lot in how they react to caffeine, though, and some feel the effects at much lower doses.
- Signs of too much: jitters, feeling anxious, a fast heart rate, headache, nausea and trouble sleeping.
- Pregnancy: the usual advice is under 200 mg a day. See coffee when pregnant.
- Children and teens: the American Academy of Pediatrics discourages caffeine for children and adolescents.
- Concentrated caffeine: the FDA warns that very large doses taken quickly, around 1,200 mg, can cause toxic effects such as seizures. That is a risk with caffeine powders and pills, not normal coffee drinking.
How Caffeine Works
During the day your brain builds up adenosine, a chemical that makes you feel sleepy. Caffeine blocks adenosine from doing its job, which is why you feel more alert. It takes the body several hours to clear caffeine, which is why an afternoon coffee can still affect your sleep at night.
Does Decaf Coffee Have Caffeine?
Yes, a little. Decaffeination removes most of the caffeine from the green beans before roasting, but not all of it. Mayo Clinic puts an 8-ounce cup of decaf at about 2 mg, and some decafs test higher. If you drink several cups, it adds up. Read more on how decaf coffee is made.
Sources
- Mayo Clinic. Caffeine content for coffee, tea, soda and more.
- U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine Is Too Much?
Former roastery owner and coffee tour operator. Steve spent five years roasting coffee for his own shop and wholesale customers. More about Steve