Diet Coke vs Starbucks London Fog: which has more caffeine?

Diet Coke has more caffeine than Starbucks London Fog on both counts: 46mg per 12 oz can against 40mg per 16 oz grande (40mg at every size), and about 4mg 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.

Diet Coke vs Starbucks London Fog: the numbers

Sources: Diet Coke's figure is verified in our Diet Coke caffeine guide against Caffeine Informer (source); Starbucks London Fog's figure is verified in our Starbucks London Fog guide against Starbucks nutrition listing (source).

Which one should you pick?

Pick Starbucks London Fog when you want the lighter dose or a slower ramp, and Diet Coke 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
• Starbucks London Fog: the full caffeine guide
• The verified caffeine database
• Every drink compared: the comparisons index

FAQ

Does Diet Coke or Starbucks London Fog have more caffeine? Diet Coke: 46mg per 12 oz can versus 40mg per 16 oz grande (40mg at every size) for Starbucks London Fog.

Which is stronger per ounce? Diet Coke, at about 3.8mg per fluid ounce versus 2.5mg for Starbucks London Fog.