Starbucks Refreshers vs Diet Coke: which has more caffeine?

Diet Coke has more caffeine than Starbucks Refreshers on both counts: 46mg per 12 oz can against 45mg per 16 oz grande, and about 4mg 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.

Starbucks Refreshers vs Diet Coke: the numbers

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

Which one should you pick?

Pick Starbucks Refreshers 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

• Starbucks Refreshers: 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 Starbucks Refreshers or Diet Coke have more caffeine? Diet Coke: 46mg per 12 oz can versus 45mg per 16 oz grande for Starbucks Refreshers.

Which is stronger per ounce? Diet Coke, at about 3.8mg per fluid ounce versus 2.8mg for Starbucks Refreshers.