Coffee has about twice the caffeine of tea, cup for cup. Cola has less than a third of what coffee has, can for can.

None of these numbers are exact. That’s fine. You don’t need exact. You need a reasonable estimate you can actually use.

The estimates, by typical serving

DrinkTypical servingCaffeine estimate
Brewed coffee8 oz (237 ml)~95 mg
Black tea8 oz (237 ml)~47 mg
Cola12 oz (355 ml)~34 mg

These are estimates for typical preparations, not a lab reading of your specific mug or can. Your coffee could run stronger or weaker depending on the beans, the brew method, and how long it sat on the machine. Treat the table as a starting point, then adjust if you know your own drink runs hot or light.

Why “how much caffeine” never has an exact answer

Ask ten people how much caffeine is in “a cup of coffee” and you’ll get ten different real answers, because “a cup of coffee” isn’t one thing. Drip coffee, French press, cold brew, and instant all extract caffeine differently, and serving sizes range widely depending on the cup, the mug, or the travel container someone actually uses.

That’s why every serious number in this space gets framed as an estimate for a typical preparation at a typical size. Anyone who hands you an exact milligram count for “coffee” without specifying the method and size is guessing with more confidence than the guess deserves.

Coffee: the biggest number, per typical cup

An 8 oz (237 ml) cup of brewed coffee runs about 95 mg of caffeine. That’s the benchmark most caffeine comparisons use, because drip brewed coffee is the most common preparation.

That 95 mg estimate is specifically for an 8 oz brewed cup. Change the size or the method and the real number moves, sometimes a lot. If you care about your actual caffeine total being accurate, the serving size matters as much as the drink type.

Tea: about half of coffee, and why

An 8 oz (237 ml) cup of black tea runs about 47 mg, roughly half of brewed coffee at the same size. Tea leaves simply carry less caffeine than coffee beans, and a typical steep pulls out less of it than a full brew cycle does for coffee.

Herbal tea (chamomile, peppermint, rooibos) has no caffeine at all, since it isn’t made from the tea plant in the first place.

What moves the number more: size or type

Doubling your serving size roughly doubles your caffeine, regardless of drink type. A 16 oz coffee carries about twice the caffeine of an 8 oz cup, using the same 95 mg per 8 oz estimate scaled up. That simple scaling matters more than people expect. A large coffee and a large soda aren’t remotely close in caffeine, but a large coffee and a small, extra-strong coffee might land closer together than the cup sizes suggest.

Soda: the smallest number, and the most sugar

A 12 oz (355 ml) can of cola runs about 34 mg, the smallest of the three despite the larger typical serving size. Soda’s real issue for most people isn’t caffeine, it’s the sugar that comes along with it, which is a separate conversation from hydration entirely.

Why WaterDrop tracks caffeine without warning you

Every drink you log gets a caffeine estimate alongside its hydration estimate: coffee at about 95 mg per 8 oz, tea at about 47 mg, and so on. You can see your running total for the day and edit any single entry if your actual cup ran stronger or weaker than the default.

What the app doesn’t do is warn you, cap you, or throw up a “you’ve had too much caffeine today” message. It’s not the app’s job to decide what’s too much for your body. It shows you the number. You decide what to do with it.

That’s a deliberate choice, not an oversight. A tracking tool that starts lecturing you stops being a tool you want to open.

Building your own baseline

If you know your actual coffee runs stronger or weaker than a standard drip brew, WaterDrop lets you edit the caffeine estimate on any logged drink instead of forcing you to accept the default. Over a week or two, your log becomes a more accurate picture of your own habits than any generic table, including this one, could ever be.

What the numbers are actually for

Most people don’t need to hit an exact caffeine target. They need a rough sense of where they stand, especially if they’re trying to cut back, or trying to figure out why they can’t fall asleep after a 4pm iced tea that “wasn’t even coffee.” Seeing 47 mg next to that tea, and comparing it to the 95 mg in the coffee they had that morning, makes the picture a lot clearer than guessing.

If caffeine is affecting your sleep or anything else feels off, that’s a conversation for your doctor, not a running total in an app. Your body, your doctor.

FAQ

How much caffeine is in a cup of coffee? About 95 mg for a typical 8 oz (237 ml) brewed cup. This is an estimate for a common preparation, not a measurement of your specific cup.

How much caffeine is in tea compared to coffee? Black tea runs about 47 mg per 8 oz, roughly half of brewed coffee at the same size. Herbal tea has none, since it isn’t made from the tea plant.

How much caffeine is in a can of soda? About 34 mg for a 12 oz (355 ml) can of cola, the smallest of the three common drinks compared here.

Does WaterDrop warn me if I’ve had too much caffeine? No. It tracks your estimated total and lets you edit any entry, but it doesn’t cap you or lecture you. The numbers are yours to interpret.

Does a bigger cup mean proportionally more caffeine? Roughly, yes. Caffeine scales with serving size for the same drink and method, so a 16 oz coffee runs about double a 8 oz coffee brewed the same way. Switching methods or drink types changes the picture more than switching cup sizes does.

Related reads:

Sources

This article is general information, not medical advice. Talk to a qualified professional about anything affecting your health.

— Dolce