Dunkin iced coffee (medium) has more caffeine than Coca-Cola Zero Sugar on both counts: 297mg per 24 oz medium against 34mg per 12 oz can, and about 12mg per fluid ounce against 3. 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.
Coca-Cola Zero Sugar vs Dunkin iced coffee (medium): the numbers
| Coca-Cola Zero Sugar | Dunkin iced coffee (medium) | |
|---|---|---|
| Caffeine per serving | 34mg per 12 oz can | 297mg per 24 oz medium |
| Caffeine per fl oz | 2.8mg | 12.4mg |
| Servings to reach 400mg (FDA context) | 11.8 | 1.3 |
Sources: Coca-Cola Zero Sugar's figure is verified in our Coca-Cola Zero Sugar caffeine guide against Caffeine Informer (source); Dunkin iced coffee (medium)'s figure is verified in our Dunkin iced coffee (medium) guide against Caffeine Informer Dunkin guide (source).
The concentration gap is the striking part: Dunkin iced coffee (medium) packs roughly 4 times the caffeine per ounce. Sipping speed matters at that density; a 24 oz medium finished in minutes hits differently than the same milligrams spread over a slow cup.
Which one should you pick?
Pick Coca-Cola Zero Sugar when you want the lighter dose or a slower ramp, and Dunkin iced coffee (medium) 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
- Coca-Cola Zero Sugar: the full caffeine guide
- Dunkin iced coffee (medium): the full caffeine guide
- The verified caffeine database
- Every drink compared: the comparisons index
- Compare any two of 120+ drinks
FAQ
Does Coca-Cola Zero Sugar or Dunkin iced coffee (medium) have more caffeine? Dunkin iced coffee (medium): 297mg per 24 oz medium versus 34mg per 12 oz can for Coca-Cola Zero Sugar.
Which is stronger per ounce? Dunkin iced coffee (medium), at about 12.4mg per fluid ounce versus 2.8mg for Coca-Cola Zero Sugar.
Barista Life runs on coffee people. Browse the Barista Life shop to support the site.