Coffee

Short answerA standard 1 oz shot of espresso carries about 63 mg of caffeine. Starbucks pulls a larger shot at roughly 75 mg. The FDA describes 400 mg a day as not generally associated with negative effects in healthy adults — about six standard shots.

How Many Espresso Per Day? answer card

How Many Espresso Per Day?

The FDA’s 400 mg daily ceiling works out to about six single shots of espresso, or three doubles. Sensitivity varies widely, and anything after mid afternoon can cost you sleep.

How Much Caffeine Is In 6 Shots Of Espresso? answer card

How Much Caffeine Is In 6 Shots Of Espresso?

Six shots of espresso carry about 378 mg of caffeine, which sits right at the FDA’s 400 mg daily ceiling. Pulled at Starbucks strength the same six shots reach roughly 450 mg.

How Much Caffeine In Two Shots Of Espresso? answer card

How Much Caffeine In Two Shots Of Espresso?

Two shots of espresso carry about 126 mg of caffeine – roughly the same as a 12 oz mug of drip coffee, and about a third of the 400 mg the FDA treats as a safe daily ceiling.

How Much Caffeine In Starbucks Doubleshot? answer card

How Much Caffeine In Starbucks Doubleshot?

A 6.5 oz can of Starbucks Doubleshot Espresso and Cream carries 125 mg of caffeine. The 15 oz Doubleshot Energy can carries 135 mg, and a doubleshot pulled in store is about 150 mg.

How Much Caffeine In One Shot Of Espresso? answer card

How Much Caffeine In One Shot Of Espresso?

A standard 1 oz shot of espresso carries about 63 mg of caffeine. Real shots range from roughly 47 to 75 mg depending on the bean, the dose and the grind; Starbucks pulls stronger shots at about 75 mg.

The whole table, in one place

ShotsStandard espressoStarbucks strengthShare of the 400 mg cap
1 shot63 mg75 mg16%
2 shots126 mg150 mg32%
3 shots189 mg225 mg47%
4 shots252 mg300 mg63%
5 shots315 mg375 mg79%
6 shots378 mg450 mg95%

Every article in this section works from this table, which is why no two pages here will give you different answers to the same question.

Why espresso is strong but a mug of drip wins

Espresso is the most concentrated way to drink coffee and one of the weakest servings by total caffeine. Concentration and dose are different things. A shot is 1 oz of very strong liquid pulled from 7 to 9 g of grounds; a 12 oz mug of drip is a weaker liquid pulled from 15 to 20 g. More grounds and more water mean more caffeine in the cup, even though each mouthful is milder.

DrinkCaffeine
Single espresso, 1 oz63 mg
Double espresso, 2 oz126 mg
Drip coffee, 12 ozabout 140 mg
Instant coffee, 8 ozabout 60 mg
Black tea, 8 ozabout 47 mg
Cola, 12 ozabout 34 mg
Energy drink, 8 ozabout 80 mg

What moves the number

VariableEffect on a shot
Robusta in the blendUp sharply — roughly twice the caffeine of arabica by weight
Double basket, 18 g doseRoughly doubles it — what many bars serve as a "single"
Ristretto, short pullDown 10 to 20 percent
Lungo, long pullUp 10 to 20 percent
Dark roastSlightly down by weight — roasting burns off a little caffeine
DecafNot zero: about 3 to 8 mg per shot

The largest source of confusion is the word "shot" itself. In Italy a single is 7 g and 1 oz. In most speciality bars elsewhere the default basket is 18 g, so what you are handed as a single espresso is closer to two Italian shots.

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, so half of what you drink at 4pm is still circulating at 10pm. That is the mechanism behind the common complaint that caffeine has no effect but sleep is poor anyway: tolerance builds against the alertness effect far faster than against the sleep disruption. 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.