A 12-ounce cup of brewed coffee contains roughly 113 to 247 milligrams of caffeine, with most cups landing somewhere around 144 mg. That wide range exists because caffeine content depends on the type of bean, how dark it’s roasted, and how it’s brewed. Here’s what shifts that number up or down.
Caffeine by Brewing Method
The way you make your coffee changes how much caffeine ends up in the cup. Standard drip coffee, the kind most people brew at home or get from a basic coffee maker, averages about 144 mg per 12-ounce serving (roughly 12 mg per ounce).
Cold brew runs noticeably higher. A 12-ounce cold brew averages around 207 mg of caffeine, about 17 mg per ounce. That’s because cold brew steeps ground coffee in water for 12 to 24 hours, extracting more caffeine during that long contact time. If you’re trying to moderate your intake, this is worth knowing: switching from drip to cold brew adds roughly 60 extra milligrams per cup.
Espresso is concentrated but served in small amounts. A single shot (about 1 ounce) packs around 63 mg of caffeine. So a 12-ounce latte made with one or two shots will typically contain less caffeine than a plain 12-ounce drip coffee, despite tasting “stronger.”
How Bean Type Affects Caffeine
The two main species of coffee bean, Arabica and Robusta, have very different caffeine levels. Arabica beans contain about 1.2 to 1.5% caffeine by weight. Robusta beans contain 2.2 to 2.7%, nearly double. Most specialty coffee shops and grocery store brands use Arabica, which is considered smoother and more flavorful. But cheaper blends, instant coffees, and some espresso blends mix in Robusta, which bumps the caffeine content significantly.
If a bag doesn’t specify, it’s most likely Arabica. If it says “high caffeine” or “extra strong,” it probably contains Robusta or a blend of both.
Light Roast vs. Dark Roast
There’s a persistent belief that dark roast coffee has more caffeine because it tastes bolder. The reality is more nuanced. A 2018 study found that a serving of light roast brewed coffee contained about 60 mg of caffeine, while the same amount of dark roast contained about 51 mg. Light roast actually had slightly more.
Here’s why: roasting doesn’t destroy much caffeine, but it does cause beans to puff up and lose density. If you scoop your coffee by volume (tablespoons), you’ll pack more light roast beans into each scoop because they’re smaller and denser, which means more caffeine per cup. If you weigh your coffee on a scale, the difference between roasts is minimal. For most home brewers who scoop rather than weigh, light roast will deliver a bit more caffeine per cup.
Decaf Still Contains Some Caffeine
Decaf isn’t truly caffeine-free. A 10- to 12-ounce cup of decaf brewed coffee contains about 7 to 8 mg of caffeine. That’s a small fraction of regular coffee, but it’s not zero. For most people, this amount is negligible. If you’re highly sensitive to caffeine or avoiding it for medical reasons, those single-digit milligrams can still matter, especially if you’re drinking multiple cups.
How 12 Ounces Fits Into Daily Limits
The FDA considers up to 400 mg of caffeine per day a safe amount for most healthy adults. That works out to roughly two to three 12-ounce cups of regular drip coffee, depending on strength. At the average of 144 mg per cup, you’d hit that ceiling at about 2.75 cups.
Cold brew tightens that math. At 207 mg per 12-ounce serving, two cups already put you at 414 mg, just over the guideline. If you drink cold brew, you have less room for other caffeine sources like tea, chocolate, or energy drinks throughout the day.
Keep in mind that individual tolerance varies widely. Some people metabolize caffeine quickly and feel fine after three cups. Others feel jittery or have trouble sleeping after just one. Genetics, body weight, medications, and how regularly you drink coffee all influence where your personal comfort zone sits.
Quick Caffeine Comparison per 12 Ounces
- Drip coffee: ~144 mg
- Cold brew: ~207 mg
- Latte (2 espresso shots + milk): ~126 mg
- Decaf brewed coffee: ~7–8 mg
The biggest factors you can control are brewing method and bean type. Switching from cold brew to drip, or from Robusta to Arabica, can meaningfully change your daily caffeine intake without changing how many cups you drink.