Reign Storm has more caffeine than Starbucks London Fog on both counts: 200mg per 12 oz can against 40mg per 16 oz grande (40mg at every size), and about 17mg per fluid ounce against 2. 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.
Starbucks London Fog vs Reign Storm: the numbers
| Starbucks London Fog | Reign Storm | |
|---|---|---|
| Caffeine per serving | 40mg per 16 oz grande (40mg at every size) | 200mg per 12 oz can |
| Caffeine per fl oz | 2.5mg | 16.7mg |
| Servings to reach 400mg (FDA context) | 10.0 | 2.0 |
Sources: Starbucks London Fog's figure is verified in our Starbucks London Fog caffeine guide against Starbucks nutrition listing (source); Reign Storm's figure is verified in our Reign Storm guide against Caffeine Informer (source).
The concentration gap is the striking part: Reign Storm packs roughly 7 times the caffeine per ounce. Sipping speed matters at that density; a 12 oz can finished in minutes hits differently than the same milligrams spread over a slow cup.
Which one should you pick?
Pick Starbucks London Fog when you want the lighter dose or a slower ramp, and Reign Storm 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
- Starbucks London Fog: the full caffeine guide
- Reign Storm: the full caffeine guide
- The verified caffeine database
FAQ
Does Starbucks London Fog or Reign Storm have more caffeine? Reign Storm: 200mg per 12 oz can versus 40mg per 16 oz grande (40mg at every size) for Starbucks London Fog.
Which is stronger per ounce? Reign Storm, at about 16.7mg per fluid ounce versus 2.5mg for Starbucks London Fog.
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.