English breakfast tea has more caffeine than Starbucks London Fog on both counts: 47mg per 8 oz cup against 40mg per 16 oz grande (40mg at every size), and about 6mg per fluid ounce against 2. The serving sizes differ, so the table below shows both ways of counting.
Starbucks London Fog vs English breakfast tea: the numbers
| Starbucks London Fog | English breakfast tea | |
|---|---|---|
| Caffeine per serving | 40mg per 16 oz grande (40mg at every size) | 47mg per 8 oz cup |
| Caffeine per fl oz | 2.5mg | 5.9mg |
| Servings to reach 400mg (FDA context) | 10.0 | 8.5 |
Sources: Starbucks London Fog's figure is verified in our Starbucks London Fog caffeine guide against Starbucks nutrition listing (source); English breakfast tea's figure is verified in our English breakfast tea guide against Twinings published figure (source).
Which one should you pick?
Pick Starbucks London Fog when you want the lighter dose or a slower ramp, and English breakfast tea 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
- English breakfast tea: the full caffeine guide
- The verified caffeine database
FAQ
Does Starbucks London Fog or English breakfast tea have more caffeine? English breakfast tea: 47mg per 8 oz cup versus 40mg per 16 oz grande (40mg at every size) for Starbucks London Fog.
Which is stronger per ounce? English breakfast tea, at about 5.9mg per fluid ounce versus 2.5mg for Starbucks London Fog.
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