Black coffee contains about 2 calories per 8-ounce cup. That’s so low it’s essentially a zero-calorie drink, and it won’t affect your diet, your fasting window, or your calorie count in any meaningful way.
Where Those 2 Calories Come From
When hot water passes through ground coffee beans, it extracts tiny amounts of protein and other organic compounds. An 8-ounce cup of brewed black coffee contains roughly 0.3 grams of protein, zero fat, and zero carbohydrates. Those 2.4 calories come almost entirely from that trace protein. There’s nothing hidden in black coffee that would bump the number higher.
This is also why coffee labels can legally say “zero calories.” The FDA allows any food or beverage with fewer than 5 calories per serving to use terms like “calorie free” or “zero calories” on its packaging. Black coffee falls well under that threshold.
Calories by Brewing Method
The way you brew your coffee barely changes the calorie count. An 8-ounce serving of drip coffee, iced black coffee, and nitro cold brew all land at roughly 2 calories. Espresso is more concentrated, so ounce for ounce it contains more calories, about 20 per 8-ounce volume. But nobody drinks 8 ounces of espresso. A standard single shot is 1 ounce, which works out to about 2 calories, the same as a regular cup of drip.
In short, if you’re drinking any form of plain black coffee with nothing added, you’re looking at roughly the same negligible calorie count regardless of the method.
What Actually Adds Calories
The calories in your coffee almost always come from what you put in it, not the coffee itself. A single tablespoon of heavy whipping cream adds about 52 calories. A teaspoon of sugar adds 16. A flavored creamer can add 35 calories per tablespoon, and most people pour more than one. A large coffeehouse latte with flavored syrup can easily reach 300 to 400 calories, turning what started as a 2-calorie drink into a full snack.
If you’re tracking calories or intermittent fasting, black coffee on its own is effectively free. The moment you add cream, sugar, milk, or syrup, those additions become the entire calorie story.
Black Coffee and Metabolism
There’s an interesting flip side to the calorie question. The caffeine in black coffee actually causes your body to burn slightly more energy at rest. Research published in the International Journal of Sport Nutrition and Exercise Metabolism found that as little as 100 milligrams of caffeine (roughly one cup of coffee) can increase resting energy expenditure by 3% to 4%. That means a cup of black coffee may help you burn more calories than the 2 it contains, putting it in rare “negative calorie” territory in practical terms.
This effect is modest and shouldn’t be treated as a weight-loss strategy on its own. But it does reinforce the point: black coffee is not something you need to worry about when counting calories.