A standard 8-ounce cup of brewed coffee contains roughly 95 mg of caffeine, while the same size serving of brewed black tea has about 48 mg. That means iced tea generally delivers about half the caffeine of iced coffee, sometimes less. But the actual number in your glass depends on the type of tea, how it’s brewed, and whether you’re making it at home or buying a bottle from the store.
Iced Tea vs. Iced Coffee, Side by Side
The gap between tea and coffee is consistent across serving sizes. For a typical 16-ounce iced drink (the size of a Starbucks Grande or a standard takeout cup), you’re looking at roughly 90 to 100 mg of caffeine in iced coffee compared to 50 to 80 mg in iced black tea brewed from scratch. If you’re drinking a bottled or ready-to-drink iced tea, the number drops further. The Mayo Clinic lists ready-to-drink bottled black tea at just 26 mg per 8 ounces, which works out to about 52 mg in a 16-ounce bottle.
Green tea iced drinks are lower still. Brewed green tea averages 29 mg per 8 ounces, so a 16-ounce glass of iced green tea lands around 58 mg. That’s roughly half of what you’d get from the same size iced coffee.
How Commercial Brands Compare
Store-bought and restaurant iced teas vary widely. A 16-ounce Just Ice Tea Original Black Tea contains about 80 mg of caffeine, putting it closer to iced coffee territory. Their Honey Green Tea version has 50 mg. Snapple Lemon Tea, on the other hand, has only 37 mg in the same 16-ounce bottle. Kombucha-style teas are the lightest option, ranging from 5 to 28 mg per 16 ounces depending on the brand.
At coffee shops, tea-based specialty drinks tell a different story. A Starbucks Grande Chai Latte (hot or iced) packs 95 mg of caffeine, essentially matching a cup of coffee. A Grande Matcha Latte has about 65 mg. These drinks use concentrated tea preparations, so they don’t follow the same rules as a simple glass of iced tea.
Why the Numbers Vary So Much
Brewing temperature and steeping time are the two biggest variables. Research published in Open Chemistry measured caffeine extraction from tea at different temperatures and found dramatic differences. At a lower brewing temperature (around 144°F), one minute of steeping produced only about 5.5 mg of caffeine per 100 mL. At a higher temperature (185°F), that same minute of steeping yielded roughly 21 mg. After five minutes at the higher temperature, caffeine levels climbed to about 68 mg per 100 mL.
This matters for iced tea because of how it’s prepared. If you brew tea with boiling or near-boiling water for several minutes, then pour it over ice, you’ll extract significantly more caffeine than if you cold-brew tea in the refrigerator overnight. Cold brewing uses lower temperatures over longer periods, which typically produces a smoother, less caffeinated result. Restaurant iced teas are often brewed hot and strong, then diluted with ice and water, which puts them somewhere in the middle.
The type of tea leaf matters too. Black tea generally has the most caffeine among true teas, followed by green, then white. Herbal “teas” like chamomile or peppermint contain no caffeine at all since they aren’t made from the tea plant.
The Energy Feels Different, Too
Caffeine content alone doesn’t tell the whole story. Tea contains an amino acid called L-theanine that slows caffeine absorption and promotes a calm, focused state. The result is a more gradual energy lift that tends to last longer without the sharp spike and crash that coffee sometimes causes. Coffee delivers its caffeine faster, which is why it feels more immediately stimulating but can also trigger jitters or an energy dip a few hours later.
If you’re sensitive to caffeine or prone to afternoon crashes, this difference in how the caffeine hits your system can matter more than the raw milligram count. A 60 mg iced tea might feel gentler and longer-lasting than a 95 mg iced coffee, even though it contains less caffeine overall.
How This Fits Into Daily Limits
The FDA considers up to 400 mg of caffeine per day safe for most healthy adults. That’s roughly four 8-ounce cups of brewed coffee or about eight cups of brewed black tea. If you’re drinking iced tea throughout the day, you have a lot more room before hitting that ceiling. Even three or four large iced teas would likely keep you well under 400 mg, while three large iced coffees could push you close to the limit.
For people who want steady energy without overshooting their caffeine budget, iced tea is a practical middle ground. It delivers enough caffeine to sharpen focus (most people notice effects starting around 40 mg) without the intensity of a full cup of coffee. Swapping your second or third coffee for an iced tea is one of the simplest ways to moderate your daily intake while still getting a caffeine boost.