Caffeine in Coffee: How Much Is in a Cup, Shot or Decaf?

Caffeine in coffee varies far more than most people expect. An 8-ounce mug of drip coffee, a single espresso and a large coffee-shop cup can differ by a factor of three or more, and two cups of the same size can differ widely depending on the beans and how they were brewed. This guide gives the reference figures from the U.S. Department of Agriculture (USDA), the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA), explains what drives the differences, and answers the common questions about roast, espresso, decaf and Jamaica Blue Mountain. It is general information, not medical advice.

How much caffeine is in a cup of coffee?

The table below converts the USDA FoodData Central reference values, which are given per 100 g, into typical servings (an 8 fl oz cup weighs about 237 g and a 1 fl oz espresso about 30 g), alongside the FDA's figures. Real drinks vary around these numbers.

The FDA's 12-ounce range of 113 to 247 mg is a useful reminder of how wide the spread is: the same size of cup can hold more than twice as much caffeine depending on the coffee and the brewing.

Espresso vs drip coffee: which has more caffeine?

Per ounce, espresso is far more concentrated: the USDA values work out to about 64 mg in a one-ounce shot against about 12 mg per ounce of drip coffee. Per serving, though, an 8-ounce mug of drip coffee (about 95 mg) usually has more than a single shot. A double shot, at about 128 mg on the same basis, overtakes a standard mug. Milk drinks such as lattes and cappuccinos get their caffeine from the espresso shots in them, so the number of shots, not the size of the cup, is what counts.

What changes the caffeine in your cup?

The coffee species

This is the biggest single factor. Robusta beans contain roughly 2.7% caffeine by weight against roughly 1.5% for arabica, according to the commonly cited figures summarized on Wikipedia (see robusta coffee and arabica coffee). Blends and instant coffees that include robusta can therefore deliver noticeably more caffeine than a 100% arabica coffee brewed the same way.

The amount of coffee and the ratio

More grounds in the same water means more caffeine. The National Coffee Association's drip guideline of 1 to 2 tablespoons per 6 ounces of water allows twice as much coffee at the top of the range as at the bottom, so a "strong" cup can have roughly double the caffeine of a "weak" one from the same bag.

Brew method, grind and time

Caffeine dissolves readily in hot water, but finer grinds, longer contact and hotter water all extract more of it. Cold brew uses room-temperature or cooler water but makes up for it with a long steep and a lot of coffee: the NCA's ratio of 1:4 to 1:5 makes a concentrate. How much caffeine a glass of cold brew holds therefore depends heavily on how much the concentrate is diluted. See the coffee grind size chart for typical grinds and times by method.

Roast level

Roast makes less difference than many people think. A 2024 study in Scientific Reports by Lindsey and colleagues found that under identical brewing the darkest roasts gave slightly lower caffeine concentrations than light and medium roasts, and Daily Coffee News reported that caffeine in the cup peaked at medium roasts. Because dark beans are lighter and larger, measuring by scoop rather than by weight also favors light roasts slightly. Our coffee roast levels guide covers the study in more detail.

Cup size

The simplest factor is often the largest. A 14- or 16-ounce mug holds nearly twice a standard 8-ounce cup, and many coffee-shop sizes are larger still.

How much caffeine is safe?

The FDA says 400 mg a day is an amount not generally associated with negative effects for most adults, roughly two to three 12-ounce cups of coffee by its own estimate, while noting that sensitivity and how fast people clear caffeine vary widely. EFSA's 2015 scientific opinion reached the same 400 mg daily figure for healthy adults, and added that single doses up to 200 mg (about 3 mg per kg of body weight) raise no safety concerns. EFSA notes that single doses of 100 mg may affect sleep in some adults when taken close to bedtime.

For pregnant and breastfeeding women, EFSA puts the level that raises no safety concerns for the fetus at up to 200 mg a day from all sources, and the FDA advises anyone pregnant, trying to become pregnant or breastfeeding to talk to a health care provider. For children and adolescents, EFSA proposes 3 mg per kg of body weight per day. These figures do not cover people with medical conditions or those taking medicines that interact with caffeine; ask a doctor or pharmacist if that applies to you.

How to estimate your own caffeine intake

1. Measure your cup. Check how many ounces or milliliters your usual mug or coffee-shop size holds.
2. Identify the drink. Use about 95 mg per 8 oz for brewed coffee and about 64 mg per espresso shot as a starting point, from the USDA values above.
3. Adjust for the coffee. Expect more if the coffee contains robusta or if you brew at the strong end of the ratio range, and less with a weaker ratio.
4. Add the other sources. Tea, cola, energy drinks, chocolate and some medicines all contain caffeine and count toward the daily total.
5. Compare with the guidance. Check the total against the FDA and EFSA figures above, and lower it if you notice poor sleep, jitters or a racing heart.

Decaf: how much caffeine is left?

Decaf is caffeine-reduced, not caffeine-free. The FDA gives 2 to 15 mg for an 8-ounce cup of decaf, and the USDA reference value works out to about 2 mg. Our guide to how decaf coffee is made explains the water, carbon dioxide and solvent methods used to remove it.

How much caffeine is in Blue Mountain coffee?

We have not found a published laboratory measurement of caffeine specific to Jamaica Blue Mountain, so we do not give a figure. What can be said is that Blue Mountain is 100% arabica (see Jamaica Blue Mountain coffee), so it belongs in the arabica range rather than the higher robusta range, and a cup brewed at a normal ratio should fall within the general brewed-coffee figures above. Its mild, low-bitterness taste is not a sign of low caffeine; caffeine content and flavor intensity are separate things. A "Blue Mountain blend", which may contain as little as 30% Blue Mountain under Jamaican rules, can contain other coffees, including robusta, so its caffeine depends on what makes up the rest (see Blue Mountain blend).

Disclosure: this site is published by Mamre Blue Coffee, a Jamaica Blue Mountain estate (see about us), so we rely on official and independent sources for the facts on this page.