espresso has more caffeine than Starbucks Refreshers on both counts: 63mg per 1 oz shot against 45mg per 16 oz grande, and about 63mg per fluid ounce against 3. The serving sizes differ, so the table below shows both ways of counting.
Starbucks Refreshers vs espresso: the numbers
| Starbucks Refreshers | espresso | |
|---|---|---|
| Caffeine per serving | 45mg per 16 oz grande | 63mg per 1 oz shot |
| Caffeine per fl oz | 2.8mg | 63.0mg |
| Servings to reach 400mg (FDA context) | 8.9 | 6.3 |
Sources: Starbucks Refreshers's figure is verified in our Starbucks Refreshers caffeine guide against Starbucks nutrition listing (source); espresso's figure is verified in our espresso guide against USDA FoodData Central (source).
The concentration gap is the striking part: espresso packs roughly 22 times the caffeine per ounce. Sipping speed matters at that density; a 1 oz shot finished in minutes hits differently than the same milligrams spread over a slow cup.
Which one should you pick?
Pick Starbucks Refreshers when you want the lighter dose or a slower ramp, and espresso 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
- espresso: 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 espresso have more caffeine? espresso: 63mg per 1 oz shot versus 45mg per 16 oz grande for Starbucks Refreshers.
Which is stronger per ounce? espresso, at about 63.0mg per fluid ounce versus 2.8mg for Starbucks Refreshers.
Barista Life runs on coffee people. Browse the Barista Life shop to support the site.