Tea generally has more caffeine than soda. An 8-ounce cup of brewed black tea contains about 48 mg of caffeine, while a 12-ounce can of Coca-Cola has 34 to 38 mg. Even when you account for the larger serving size of soda, tea still comes out ahead in most matchups.
Tea vs. Soda: A Side-by-Side Look
The comparison depends on which tea and which soda you’re drinking. Brewed black tea delivers roughly 48 mg of caffeine per 8-ounce cup. Brewed green tea comes in lower at about 29 mg per cup. Bottled ready-to-drink black tea splits the difference at around 26 mg per 8 ounces.
On the soda side, most mainstream colas fall in a narrow range. A 12-ounce can of Coke, Coke Zero, or Pepsi contains 34 to 38 mg. Diet Coke is actually higher than regular Coke at 46 mg. Dr Pepper lands at 41 mg, and Mountain Dew tops the mainstream list at 54 mg per can. Zero Sugar Mountain Dew goes even higher at 68 mg.
So a standard cup of black tea beats a regular Coke by about 10 mg, despite coming in a smaller serving. Green tea and a Coke are closer to a wash. Mountain Dew is one of the few common sodas that can outpace a cup of black tea.
Newer Sodas Pack More Caffeine
The “gut health” soda brands that have surged in popularity deserve their own mention. A 12-ounce can of Olipop Vintage Cola, Cherry Cola, or Ridge Rush contains about 50 mg of caffeine, comparable to Mountain Dew. Poppi’s Alpine Blast has 55 mg, while its cola and Dr Pepper-style flavors come in around 40 mg. These aren’t dramatically higher than traditional sodas, but they’re enough to close the gap with brewed tea or surpass it.
Serving Size Changes Everything
The numbers above use standard reference sizes: 8 ounces for tea, 12 ounces for soda. But few people actually drink tea in precise 8-ounce portions. A standard mug holds 10 to 12 ounces. A Starbucks tall is 12 ounces, a grande is 16, and a venti is 20. If you’re drinking a 16-ounce mug of black tea, you’re looking at roughly 96 mg of caffeine, nearly triple what’s in a can of Coke.
Soda servings are more predictable since cans come in fixed sizes, though a 20-ounce bottle from a gas station bumps the caffeine proportionally. A 20-ounce Coke has about 57 mg, while a 20-ounce Mountain Dew hits around 90 mg.
How Steep Time Affects Tea
With soda, the caffeine content is fixed at the factory. Tea is different. How long you steep it dramatically changes how much caffeine ends up in your cup. After just one minute of steeping, only about 18% of the caffeine in the tea leaves has dissolved into the water. At three minutes, that jumps to 48%. By five minutes, you’ve extracted roughly 69% of the available caffeine.
This means a quickly dunked tea bag produces a much milder drink than one left to steep for several minutes. If you’re trying to keep your caffeine intake low, pulling the tea bag early is a simple way to do it. Conversely, if you want a stronger kick, letting it sit longer costs you nothing extra.
Caffeine-Free Options Aren’t Always Equal
If you’re trying to avoid caffeine entirely, soda is the more reliable choice. Caffeine-free colas (like Caffeine-Free Coke or most root beers) test at essentially zero caffeine. Decaffeinated tea is a different story. It still contains some residual caffeine, averaging about 2 mg per cup by Mayo Clinic figures, though testing by the Connecticut Agricultural Experiment Station found a wider range of up to 21.5 mg per serving in some products. If you’re sensitive to even small amounts, a caffeine-free soda is a safer bet than decaf tea.
Most root beers and orange sodas are naturally caffeine-free, with a few exceptions. Barq’s Root Beer has 22 mg per can, and Sunkist Orange has 19 mg. Check the label if it matters to you.
How Both Fit Into Daily Limits
The FDA considers up to 400 mg of caffeine per day a safe amount for most healthy adults. That’s the equivalent of roughly eight cups of brewed black tea or ten to twelve cans of Coke. Most people aren’t coming close to that limit from tea or soda alone, though it adds up quickly if you’re also drinking coffee or energy drinks throughout the day.
One practical difference between the two: tea contains an amino acid called L-theanine that many tea drinkers say produces a smoother, less jittery alertness compared to other caffeine sources. The caffeine molecule itself is identical in tea and soda, but the overall experience of drinking them can feel different because of what else comes along with it.