Dunkin' Bottled Iced Coffee has more caffeine than Diet Coke on both counts: 197mg per 13.7 oz bottle against 46mg per 12 oz can, and about 14mg 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.
Dunkin' Bottled Iced Coffee vs Diet Coke: the numbers
| Dunkin' Bottled Iced Coffee | Diet Coke | |
|---|---|---|
| Caffeine per serving | 197mg per 13.7 oz bottle | 46mg per 12 oz can |
| Caffeine per fl oz | 14.4mg | 3.8mg |
| Servings to reach 400mg (FDA context) | 2.0 | 8.7 |
Sources: Dunkin' Bottled Iced Coffee's figure is verified in our Dunkin' Bottled Iced Coffee caffeine guide against Caffeine Informer (source); Diet Coke's figure is verified in our Diet Coke guide against Caffeine Informer (source).
The concentration gap is the striking part: Dunkin' Bottled Iced Coffee packs roughly 4 times the caffeine per ounce. Sipping speed matters at that density; a 13.7 oz bottle finished in minutes hits differently than the same milligrams spread over a slow cup.
Which one should you pick?
Pick Diet Coke when you want the lighter dose or a slower ramp, and Dunkin' Bottled Iced Coffee 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
- Dunkin' Bottled Iced Coffee: the full caffeine guide
- Diet Coke: the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
- Compare any two of 120+ drinks
FAQ
Does Dunkin' Bottled Iced Coffee or Diet Coke have more caffeine? Dunkin' Bottled Iced Coffee: 197mg per 13.7 oz bottle versus 46mg per 12 oz can for Diet Coke.
Which is stronger per ounce? Dunkin' Bottled Iced Coffee, at about 14.4mg per fluid ounce versus 3.8mg for Diet Coke.
Comparing caffeine? The caffeine comparison tool puts hundreds of drinks side by side, and the caffeine curfew calculator can check your cutoff time for tonight.