A medium coffee contains roughly 180 to 210 milligrams of caffeine, depending on where you buy it and how it’s brewed. At Dunkin’, a medium (14 oz) brewed coffee delivers about 210 mg. That single cup accounts for about half the 400 mg daily limit the FDA considers safe for most adults.
Caffeine by Chain and Cup Size
“Medium” doesn’t mean the same thing everywhere. At Dunkin’, a medium is 14 fluid ounces. At many smaller cafés and convenience stores, a medium is 12 ounces. That two-ounce difference alone can shift the caffeine count by 20 to 30 mg.
Dunkin’s medium brewed coffee clocks in at 210 mg of caffeine. If you order a medium latte or cappuccino from the same counter, the number drops to about 166 mg, because those drinks are built on espresso shots rather than a full cup of brewed coffee. Espresso is more concentrated per ounce but uses far less liquid, so espresso-based drinks generally deliver less total caffeine than a same-size drip coffee.
Drip Coffee vs. Espresso vs. Cold Brew
Brewed (drip) coffee averages about 95 mg of caffeine per 8-ounce cup, which works out to roughly 12 mg per ounce. A single shot of espresso packs about 63 mg into just one ounce, making it much more concentrated. But because a latte or cappuccino typically uses only one or two shots, the total caffeine stays lower than a full mug of drip.
Cold brew is the outlier. Because grounds steep for 12 to 24 hours in a higher coffee-to-water ratio, an 8-ounce serving of cold brew averages around 150 mg of caffeine. Scale that up to a 14- or 16-ounce medium and you could be looking at 260 to 300 mg in a single cup. If you’re watching your intake, cold brew is the drink that can catch you off guard.
Why the Same Size Cup Can Vary So Much
Several factors push caffeine content up or down, even when the cup size stays the same.
Bean type: Most specialty coffee shops use Arabica beans, which contain about 1.5% caffeine by weight. Robusta beans, commonly found in instant coffee and some cheaper blends, contain roughly 2.7%, nearly double. A medium cup made with Robusta beans can easily deliver 50% more caffeine than one made with Arabica.
Roast level: Light roasts contain slightly more caffeine than dark roasts when measured by volume. A 2018 study found that a serving of light roast brewed coffee had about 60 mg of caffeine compared to 51 mg for the same volume of dark roast. The difference is modest, though. Dark roast beans puff up and expand during roasting, so a scoop of dark roast contains less actual coffee by weight than the same scoop of denser light roast beans. If you weigh your coffee instead of scooping it, the caffeine content between roasts is nearly identical.
Brew strength and water ratio: A shop that uses more grounds per cup or a slightly longer brew time will extract more caffeine. This is why caffeine numbers from different chains don’t line up neatly, even for the same cup size.
How a Medium Fits Into Your Daily Limit
The FDA puts the safe daily ceiling for most healthy adults at 400 mg of caffeine, a number backed by a 2017 systematic review. A single medium drip coffee at 200 mg or so takes up about half that budget. Two medium coffees bring you right to the line. Rapid consumption of around 1,200 mg can cause toxic effects like seizures, but that would take roughly six medium cups consumed in quick succession, not a realistic scenario for most people.
Caffeine kicks in within about 15 to 45 minutes of drinking it, with 30 minutes being typical. Its half-life is 5 to 6 hours, meaning if you drink a 200 mg medium coffee at 3 p.m., you still have roughly 100 mg circulating at 8 or 9 p.m. That’s enough to interfere with sleep for many people, which is why timing matters as much as total intake.
Quick Caffeine Reference for a Medium Cup
- Dunkin’ brewed coffee (14 oz): 210 mg
- Dunkin’ latte or cappuccino (14 oz): 166 mg
- Generic drip coffee (12 oz): roughly 140 to 170 mg
- Cold brew (14 oz): roughly 260 to 300 mg
- FDA daily limit for most adults: 400 mg