Coffee is the biggest dietary source of caffeine.
You can expect to get around 95 mg of caffeine from an average cup of coffee.
However, this amount varies between different coffee drinks, and can range from almost zero to over 500 mg.
This is a detailed guide to the caffeine content of different types and brands of coffee.
What Factors Affect Caffeine Content?
The caffeine content of coffee depends on many factors, such as:
- Type of coffee beans: There are many varieties of coffee beans available, which may naturally contain different amounts of caffeine.
- Roasting: Lighter roasts have more caffeine than darker roasts, although the darker roasts have a deeper flavor.
- Type of coffee: The caffeine content can vary significantly between regularly brewed coffee, espresso, instant coffee and decaf coffee.
- Serving size: “One cup of coffee” can range anywhere from 30–700 ml (1–24 oz), greatly affecting the total caffeine content.
Bottom Line: Caffeine content is affected by the type of coffee bean, roast style, how the coffee is prepared and the serving size.
How Much Caffeine is in a Cup of Coffee?
The main determinant of caffeine content is the type of coffee you are drinking.
Brewing is the most common way to make coffee in the US and Europe.
Also known as regular coffee, brewed coffee is made by pouring hot or boiling water over ground coffee beans, usually contained in a filter.
One cup of brewed coffee (8 oz) contains about 70–140 mg of caffeine, or about 95 mg on average (1, 2).
Espresso is made by forcing a small amount of hot water, or steam, through finely ground coffee beans.
Although espresso has more caffeine per volume than regular coffee, it usually contains less per serving, since espresso servings tend to be small.
One shot of espresso is generally about 30–50 ml (1–1.75 oz), and contains about 63 mg of caffeine (3).
A double shot of espresso therefore contains roughly 125 mg of caffeine.
Many popular coffee drinks are made from espresso shots mixed with varying types and amounts of milk.
These include lattes, cappuccinos, macchiatos and Americanos.
Since the milk does not contain any additional caffeine, these drinks contain the same amount of caffeine as straight espresso.
A single (small) contains about 63 mg of caffeine on average, and double (large) contains about 125 mg.
Instant coffee is made from brewed coffee that has been freeze-dried or spray-dried. It is generally in large, dry pieces, which dissolve in water.
To prepare instant coffee, simply mix one or two teaspoons of dried coffee with hot water. There is no need for any brewing.
Instant coffee usually contains less caffeine than regular coffee, with one 8-oz cup (237 ml) containing roughly 30–60 mg (4).
Although the name may be deceiving, decaf coffee is not entirely caffeine free.
It may contain varying amounts of caffeine, ranging from 0–7 mg per cup, with the average cup containing 3 mg (5, 6, 7).
However, some varieties may contain even higher amounts of caffeine, depending on the type of coffee, method of de-caffeination and cup size.
Bottom Line: The average caffeine content of an 8-oz, brewed cup of coffee is 95 mg. A single espresso or espresso-based drink contains 63 mg, and decaf coffee contains about 3 mg of caffeine (on average).
Are Commercial Brands More Caffeinated?
Some commercial coffee brands contain more caffeine than regular, home-brewed coffee.
Coffee shops are also notorious for their large cup sizes, which can range up to 700 ml (24 oz). The amount of coffee in such cups is equivalent to about 3–5 regular-sized cups of coffee.
Starbucks is probably the best-known coffee shop in the world. It also offers some of the most caffeinated coffee available.
The caffeine content of brewed coffee at Starbucks is as follows (8, 9):
- Short (8 oz): 180 mg
- Tall (12 oz): 260 mg
- Grande (16 oz): 330 mg
- Venti (20 oz): 415 mg
Furthermore, one shot of espresso at Starbucks contains 75 mg of caffeine.
Consequently, all small, espresso-based drinks also contain 75 mg of caffeine. This includes lattes, cappuccinos, macchiatos and Americanos, among others (10).
Larger sizes, which are made with two, or even three, espresso shots (16 oz), likewise contain 150 or 225 mg of caffeine.
Decaf coffee from Starbucks contains 15–30 mg of caffeine, depending on cup size.
Bottom Line: An 8-oz, brewed coffee from Starbucks contains 180 mg of caffeine. A single espresso and espresso-based drink contain 75 mg, while an 8-oz cup of decaf coffee contains about 15 mg of caffeine.
McDonald’s sells coffee all over the world, often under their McCafe brand.
However, despite being one of the biggest fast food chains that sells coffee, they do not standardize or calculate the amount of caffeine in their coffee.
As an estimate, the caffeine content of their brewed coffee is about (11):
- Small (12 oz): 109 mg
- Medium (16 oz): 145 mg
- Large (21–24 oz): 180 mg
Their espresso contains 71 mg per serving, and decaf contains 8–14 mg, depending on the size of the cup.
Bottom Line: McDonald’s doesn’t standardize the amount of caffeine in their coffee. As an estimate, a small cup of brewed coffee contains 109 mg of caffeine. Espresso contains about 71 mg, and decaf has about 8 mg.
Dunkin Donuts is another chain of coffee and donut shops that is very popular worldwide. The caffeine content of their brewed coffee is as follows (12):
- Small (10 oz): 215 mg
- Medium (16 oz): 302 mg
- Large (20 oz): 431 mg
- Extra large (24 oz): 517 mg
Their single espresso shot contains 75 mg of caffeine, which is also how much you can expect to get from their espresso-based drinks.
Decaf coffee from Dunkin Donuts may also contain quite a bit of caffeine. According to one source, a small cup (10 oz) has 53 mg of caffeine, and a large cup (24 oz) contains 128 mg (13).
That’s almost as much caffeine as you find in other varieties of regular coffee.
Bottom Line: A small cup of coffee from Dunkin Donuts contains 215 mg of caffeine, while a single espresso contains 75 mg. Interestingly, their decaf coffee may contain as much as 53-128 mg of caffeine.
Is Caffeine Something to Worry About?
Coffee is high in antioxidants, and many studies show that it is good for your health.
However, getting too much caffeine is linked to adverse effects like anxiety, sleep disruptions, heart palpitations and restlessness (14, 15).
Consuming 400–600 mg/day of caffeine is generally not associated with adverse effects in most people. This is about 6 mg/kg (3 mg/lb) of body weight, or 4–6 average cups of coffee per day (16).
That being said, caffeine affects people very differently.
Some are very sensitive to it while others find themselves unaffected by large amounts. This is largely due to genetic differences (17, 18).
You’ll just have to experiment and see what amount suits you best.