A standard 8-ounce cup of brewed coffee contains roughly 100 to 150 mg of caffeine, but the actual amount varies widely depending on what you’re drinking. Tea, soda, energy drinks, chocolate, and even some pain relievers all contain caffeine in very different amounts. Here’s a practical breakdown of the most common sources.
Caffeine in Coffee
For most people, coffee is the single biggest source of caffeine in their day. An 8-ounce cup of brewed coffee delivers about 100 to 150 mg, though the exact number depends on the beans, the grind, and how it’s prepared. Espresso packs more caffeine per ounce but is served in much smaller volumes, so a single shot (about 1 ounce) typically contains 63 mg.
Roast level makes a smaller difference than most people assume. Light roast coffee actually contains slightly more caffeine than dark roast. One study measured about 60 mg in a sample of light roast and 51 mg in the same amount of dark roast. The roasting process burns off a small amount of caffeine, so darker beans lose a bit along the way. Still, the gap is modest enough that your brewing method and the amount of coffee grounds you use matter more than roast color.
Decaf coffee isn’t completely caffeine-free. By USDA standards, decaf must have at least 97% of its caffeine removed, which means a typical cup still contains 2 to 7 mg. That’s negligible for most people, but it can add up if you drink several cups.
Caffeine in Tea
Tea contains less caffeine than coffee, but the range is wide. An 8-ounce cup of brewed black tea has about 48 mg, while the same amount of green tea has around 29 mg. White tea generally falls below green tea, though the exact amount depends on the specific leaves and how they’re processed.
How long you steep your tea matters more than you might expect. Research on green tea found that caffeine extraction mostly happens in the first three minutes of brewing. At typical brewing temperatures (around 175°F to 185°F), caffeine reached its near-maximum level by the three-minute mark and didn’t increase much after that. So a one-minute steep gives you noticeably less caffeine than a three-minute steep, but leaving the bag in for ten minutes won’t dramatically increase it further. Hotter water also pulls out caffeine faster.
Caffeine in Energy Drinks
Energy drinks have the widest caffeine range of any beverage category, from 80 mg in a small Red Bull to 300 mg in a can of Bang or C4 Ultimate. Here’s how popular brands compare:
- Bang (16 oz.): 300 mg
- Celsius Essentials (16 oz.): 270 mg
- 5-hour Energy Extra Strength (1.9 oz.): 230 mg
- Celsius (12 oz.): 200 mg
- Alani Nu Energy (12 oz.): 200 mg
- Prime Energy (16 oz.): 200 mg
- Monster Energy Original (16 oz.): 160 mg
- Rockstar Original (16 oz.): 160 mg
- Red Bull (8.4 oz.): 80 mg
Pay attention to serving sizes. A 16-ounce can of Monster has 160 mg, which is comparable to a strong cup of coffee. But a 16-ounce Bang has nearly double that. The concentrated 5-hour Energy shots pack 200 to 230 mg into less than 2 ounces, making it easy to consume a large dose very quickly.
Caffeine in Soda
Sodas sit at the lower end of the caffeine spectrum. A 12-ounce can of Coca-Cola has 34 mg, and Pepsi has 35 to 38 mg. Diet Coke is actually higher than regular Coke at 46 mg. Mountain Dew leads the mainstream soda category with 54 mg per 12-ounce can (68 mg for the zero-sugar version).
Dr Pepper lands at 41 mg, and Barq’s Root Beer has 22 mg. Several popular sodas contain zero caffeine: Sprite, 7UP, Fanta Orange, ginger ale, A&W Root Beer, and Mug Root Beer are all caffeine-free.
Caffeine in Chocolate and Medications
Dark chocolate contains about 12 mg of caffeine per ounce according to the USDA. A typical chocolate bar (around 1.5 ounces) gives you roughly 18 mg. Milk chocolate has less, and white chocolate has essentially none since it doesn’t contain cocoa solids. Chocolate isn’t a major caffeine source for most people, but it’s worth knowing about if you’re sensitive or snacking late at night.
Some over-the-counter pain relievers also contain caffeine. Excedrin and similar migraine-relief tablets include 65 mg of caffeine per dose alongside their other active ingredients. Caffeine is added because it helps the body absorb pain relievers more effectively and can improve headache relief on its own. Two tablets bring you to 130 mg, which is roughly equivalent to a cup of coffee.
How Much Is Safe Per Day
The FDA considers 400 mg of caffeine per day a safe upper limit for most healthy adults. That’s roughly two to three 12-ounce cups of brewed coffee, or two standard 16-ounce energy drinks (depending on the brand). Staying under this threshold generally avoids the negative effects of caffeine, which include anxiety, disrupted sleep, a racing heartbeat, and digestive discomfort.
During pregnancy, the recommended limit drops significantly. The American College of Obstetricians and Gynecologists advises keeping intake under 200 mg per day, noting that moderate consumption below that level does not appear to be a major factor in miscarriage or preterm birth. That’s roughly one 8-ounce cup of coffee or four cups of black tea.
How Long Caffeine Stays in Your System
Caffeine takes about 15 to 45 minutes to kick in after you consume it, with most people feeling the effects within half an hour. Its half-life is 5 to 6 hours, meaning that if you drink 200 mg of caffeine at noon, roughly 100 mg is still active in your body by 5 or 6 p.m. After another 5 to 6 hours, about 50 mg remains.
This is why afternoon coffee can interfere with sleep even when you feel fine at bedtime. If you’re sensitive to caffeine’s effects on sleep, your last cup by early afternoon gives your body enough time to clear most of it before night. Genetics, age, liver function, and certain medications all influence how quickly you metabolize caffeine, so some people clear it faster than others.