Diet Coke vs brewed black tea: which has more caffeine?

brewed black tea has more caffeine than Diet Coke on both counts: 47mg per 8 oz cup against 46mg per 12 oz can, and about 6mg per fluid ounce against 4. The serving sizes differ, so the table below shows both ways of counting.

These are different categories of drink, which changes how the caffeine arrives. Energy drinks and sodas list an exact number because caffeine is a measured additive; brewed drinks vary with the beans and the brew, so their figures are compiled averages. The numbers here are the standard published values for each.

Diet Coke vs brewed black tea: the numbers

Sources: Diet Coke's figure is verified in our Diet Coke caffeine guide against Caffeine Informer (source); brewed black tea's figure is verified in our brewed black tea guide against USDA FoodData Central (source).

Which one should you pick?

Pick Diet Coke when you want the lighter dose or a slower ramp, and brewed black tea when you actually need the bigger hit and know your tolerance. If you are stacking either with other caffeinated drinks through the day, run the math against the 400mg reference rather than guessing.

For context, the FDA cites 400mg of caffeine a day as an amount generally not associated with negative effects in healthy adults. Tolerance and health vary, so treat these numbers as information, not advice.

Related reading

• Diet Coke: the full caffeine guide
• brewed black tea: the full caffeine guide
• The verified caffeine database
• Every drink compared: the comparisons index

FAQ

Does Diet Coke or brewed black tea have more caffeine? brewed black tea: 47mg per 8 oz cup versus 46mg per 12 oz can for Diet Coke.

Which is stronger per ounce? brewed black tea, at about 5.9mg per fluid ounce versus 3.8mg for Diet Coke.