Water Joe (caffeinated water) has more caffeine than Diet Coke on both counts: 70mg per 16.9 oz bottle against 46mg per 12 oz can, and about 4mg per fluid ounce against 4. The serving sizes differ, so the table below shows both ways of counting.
Water Joe (caffeinated water) vs Diet Coke: the numbers
| Water Joe (caffeinated water) | Diet Coke | |
|---|---|---|
| Caffeine per serving | 70mg per 16.9 oz bottle | 46mg per 12 oz can |
| Caffeine per fl oz | 4.1mg | 3.8mg |
| Servings to reach 400mg (FDA context) | 5.7 | 8.7 |
Sources: Water Joe (caffeinated water)'s figure is verified in our Water Joe (caffeinated water) caffeine guide against Water Joe / Caffeine Informer (source); Diet Coke's figure is verified in our Diet Coke guide against Caffeine Informer (source).
Which one should you pick?
Pick Diet Coke when you want the lighter dose or a slower ramp, and Water Joe (caffeinated water) 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
- Water Joe (caffeinated water): 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 Water Joe (caffeinated water) or Diet Coke have more caffeine? Water Joe (caffeinated water): 70mg per 16.9 oz bottle versus 46mg per 12 oz can for Diet Coke.
Which is stronger per ounce? Water Joe (caffeinated water), at about 4.1mg per fluid ounce versus 3.8mg for Diet Coke.
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