A double shot of espresso carries about 126 mg of caffeine — two 63 mg shots. At Starbucks the same drink runs closer to 150 mg, because their shots are pulled larger.
Related conversions
Pulled as two separate shots the total is identical. A single is about 63 mg. The canned version is Starbucks Doubleshot. Against the daily ceiling, see how many espressos per day. More under coffee answers.
The number
| Shots | Standard espresso | Starbucks strength | Share of the 400 mg daily cap |
|---|---|---|---|
| 1 shot | 63 mg | 75 mg | 16% |
| 2 shots | 126 mg | 150 mg | 32% |
| 3 shots | 189 mg | 225 mg | 47% |
| 4 shots | 252 mg | 300 mg | 63% |
| 5 shots | 315 mg | 375 mg | 79% |
| 6 shots | 378 mg | 450 mg | 94% |
The standard column uses 63 mg per 1 oz shot pulled from 7 to 9 g of grounds. Starbucks pulls a larger, longer shot at roughly 75 mg.
The last column is measured against the 400 mg per day the FDA describes as not generally associated with negative effects for healthy adults.
Why this is a range, not a constant. Caffeine extraction depends on the bean, the dose, the grind and the length of the pull. Robusta carries roughly twice the caffeine of arabica by weight.
A ristretto pulled short from the same dose lands lower; a lungo pulled long lands higher. Treat every figure here as a planning number accurate to within about fifteen percent, not a laboratory result.
The double is the real default
Outside Italy, a double is what most cafes actually pull. The standard basket in a modern espresso machine holds 18 to 20 g of coffee, which is a double dose; ordering “an espresso” in a speciality bar in London, Melbourne or Seattle usually gets you that.
If you have been counting your daily intake in singles, there is a fair chance you have been drinking doubles.
That matters for the arithmetic. Four coffees a day at 63 mg each is 252 mg, comfortably inside the guideline. Four doubles is 504 mg, which is over it.
How it compares
| Drink | Caffeine |
|---|---|
| Single espresso, 1 oz | 63 mg |
| Double espresso, 2 oz | 126 mg |
| Drip coffee, 12 oz | about 140 mg |
| Instant coffee, 8 oz | about 60 mg |
| Black tea, 8 oz | about 47 mg |
| Cola, 12 oz | about 34 mg |
| Energy drink, 8 oz | about 80 mg |
The surprise for most people is the drip row. A single espresso is a concentrated shot, but a mug of filter coffee is a far larger volume — and it wins on total caffeine nearly every time.
Where the drink names diverge
| Drink | Espresso in it | Caffeine |
|---|---|---|
| Doppio, double espresso | 2 shots | 126 mg |
| Americano, regular | 2 shots | 126 mg |
| Latte or cappuccino, small | 1 shot | 63 mg |
| Latte or cappuccino, large | 2 shots | 126 mg |
| Flat white | 2 shots | 126 mg |
| Macchiato | 1 to 2 shots | 63 to 126 mg |
Milk changes nothing about the caffeine. A large latte and a double espresso are the same drink as far as your nervous system is concerned; the milk only changes how quickly it arrives, and even that effect is modest.
When you drink it matters as much as how much
Caffeine has a half-life of roughly five to six hours in a healthy adult, meaning half of what you drink at 4pm is still circulating at 10pm.
That is the mechanism behind the common complaint that “caffeine does not affect me, but I sleep badly” — tolerance builds against the alertness effect far faster than against the sleep disruption.
Genetics play a large part too. Variation in the CYP1A2 enzyme means some people clear caffeine in half the time others take, which is why a shared cut-off time is useless advice and a personal one is worth finding.
Common questions
Is a double shot too much at once?
For most healthy adults, no — 126 mg is about a third of the daily guideline and less than a large mug of filter coffee.
The people who should be more careful are those who are pregnant, taking certain medications, or unusually sensitive.
Why does the same double feel different at different cafes?
Dose and bean. An 18 g arabica double and a 20 g robusta-blend double can differ by seventy percent in caffeine while looking identical in the cup.
Does a double hit faster than two singles?
Marginally, because you drink it in one go. Peak blood concentration lands 30 to 60 minutes after the last sip either way.
Sources
- U.S. Food and Drug Administration — Spilling the Beans: How Much Caffeine is Too Much? (the 400 mg per day figure for healthy adults)
- U.S. Department of Agriculture — FoodData Central (caffeine content of brewed espresso and coffee)
Figures on this page are planning numbers, not measurements of your particular drink. Caffeine per shot varies with the bean, the dose, the grind and the length of the pull.
