How Much Caffeine Is in a Cup of Coffee?

Medically reviewed by Suzanne Fisher, RD

The stimulating effect of caffeine is one of the main reasons so many people enjoy a daily cup of coffee. You can expect an 8-ounce cup of coffee to provide just under 100 milligrams (mg) of caffeine and a 12-ounce cup with approximately 140 mg.

But where does that fall in terms of recommended daily allowances of caffeine? Can you expect similar caffeine amounts from home-brewed coffee vs. a cup you pick up from a coffee shop?

This article examines how much caffeine you can expect from your coffee, including factors influencing caffeine content, and gives a general guideline on daily caffeine limits.

Related: Is Coffee Bad for You?

Milligrams of Caffeine in One Cup of Coffee

The amount of caffeine in a standard cup of coffee can vary depending on factors such as the type of coffee beans, the brewing method, and the serving size. On average, an 8-ounce cup of brewed coffee contains approximately 90–95 milligrams (mg) of caffeine.

However, this amount can fluctuate, with some cups containing as little as 70 mg and others having as much as 140 mg or more. In addition, if you drink decaffeinated coffee, you are still getting some caffeine. On average, an 8-ounce cup of decaf coffee contains around 2–5 mg of caffeine.

It's important to be mindful of caffeine intake, especially if you're sensitive to caffeine's effects. Following is a closer look at some of the main factors involved in determining caffeine amounts.

Coffee Size

Not all cups and mugs of coffee of the same portion size. Logically, there's 3 times as much caffeine in a 24-ounce mug vs. an 8-ounce cup of the same brew.

If your goal is to keep your daily caffeine intake to an allotted amount, it may be best to opt for a smaller portion, especially if you drink more than one coffee daily.

Coffee Type

Certain types of coffee and brewing techniques result in slightly higher caffeine levels. However, some studies have found no significant differences in caffeine content when comparing specialty-grade brews to other popular brands.

Some of the types of coffee that may have the most caffeine per serving are:

• Robusta coffee beans: Robusta beans typically contain more caffeine than Arabica beans. Robusta beans are often used in espresso blends and instant coffee, contributing to higher caffeine levels in these types of coffee.

• Dark roast coffee: Contrary to popular belief, dark roast coffee beans usually contain slightly less caffeine than lighter roasts. However, dark roast coffee often has a bolder flavor, which may give the perception of a higher caffeine content.

• Espresso: While espresso shots are smaller in volume than a standard cup of coffee, they tend to have a higher concentration of caffeine due to the brewing method: the pressure and short extraction time used in making espresso extract more caffeine from the coffee grounds.

• Cold brew coffee: Cold brew coffee is made by steeping coffee grounds in cold water for an extended period, typically 12 to 24 hours. This method extracts a higher caffeine concentration than traditional hot brewing methods, resulting in a coffee beverage with more caffeine per ounce.

• Turkish coffee: Turkish coffee is prepared by boiling finely ground coffee beans with water and sugar. Since the coffee grounds are not filtered out, Turkish coffee tends to have a higher caffeine content than espresso.

Remember that caffeine content can vary within these categories based on factors like bean origin, blend composition, and brewing technique.

To-Go Coffee Brands

There may be differences in caffeine content depending on where you pick up your coffee. For example, Starbucks brand coffee may use very different beans and brewing methods than the coffee you buy from a convenience store.

Some coffee drinks may have added flavoring, syrups, or enhancers, which can also affect the caffeine content. Caffeine content also depends on the roasting level of coffee. Darker roasts tend to have less caffeine than lighter roasts, because the longer roasting process breaks down some of the caffeine molecules in the dark beans.

Related: Everything You Need to Know About Caffeine

Caffeine Content in Coffee Compared to Other Drinks

Coffee is not the only beverage people drink for an energy boost. Teas and sodas contain caffeine, too.

Tea

Brewing methods, the type of leaf used to make it, and serving size contribute to the amount of caffeine in a cup of tea. Typically, coffee contains more caffeine per serving than tea.

Compared to the 95 mg of caffeine in an 8-ounce coffee, the same serving of black tea contains approximately 40–70 mg. Of course, these amounts can differ based on the type of coffee bean or tea leaf compared and the brewing time.

Additionally, certain types of tea, like green or white, generally contain less caffeine than black tea.

Soda

A can of cola contains significantly more added than a cup of black coffee, but coffee has more caffeine.

Compared to the 95 mg of caffeine in an 8-ounce cup of coffee, a 12-ounce can of cola generally contains much less caffeine, ranging from about 20 mg to 40 mg. However, there are always exceptions. Certain energy drinks and specialty sodas designed to boost energy or alertness may contain even higher levels of caffeine.

The type of coffee or soda, plus how much you drink at a time, can also influence caffeine content. While you may enjoy coffee for its rich flavor and higher caffeine content, consider carbonated soda, which is a lower-caffeine option.

What’s Considered a Lot of Caffeine?

When it comes to caffeine, the answer to how much is too much depends on the individual. For instance, limits can be influenced by factors like caffeine tolerance, sensitivity, and overall health.

Generally speaking, consuming more than 400 mg of caffeine daily is often considered excessive for most healthy adults. This amount is roughly equivalent to four 8-ounce cups of brewed coffee.

Exceeding this threshold may be more likely to cause unwanted effects, such as the following:

• Jitteriness

• A faster heart rate

• Difficulty sleeping

• Digestive discomfort

• Headaches

Depending on tolerance, in some people, even smaller amounts of caffeine can trigger adverse side effects.

It's important to recognize that coffee may not be your only source of caffeine in a day. If you're monitoring your caffeine intake, you should be aware of other sources, such as tea, soda, energy drinks, chocolate, and supplements.

Optimal Amount of Daily Cups of Coffee

The maximum amount of coffee to drink daily is subjective, but do keep in mind any adverse side effects you may experience when overdoing it. Plain water is considered the best source of hydration.

When determining the optimal amount of daily coffee for you, consider factors like your caffeine sensitivity, health considerations, and lifestyle habits. Consuming one to four cups of coffee daily is considered moderate and generally safe for many adults. It may even offer anti-inflammatory and antioxidant benefits. Some research has found that coffee consumption may have protective effects against metabolic syndrome, type 2 diabetes, and several types of cancer.

However, factors like age, pregnancy status, underlying health conditions, and medication interactions may warrant adjustments to coffee consumption. If you're unsure whether your caffeine intake is ideal, it's best to consult a healthcare provider for personalized advice.

Related: There Are So Many Health Studies on Coffee. Which One Should You Trust?

Summary

Many people consider coffee one of life's pleasurable daily routines, but coffee is a major source of caffeine. Depending on the type of coffee, where you get it, how it's brewed, and how much of it you drink, the caffeine content varies.

An 8-ounce cup generally contains around 95 mg of caffeine. How much caffeine per day is best for you depends on your level of tolerance and health factors, but for most people, daily moderate intake is considered safe.

Read the original article on Verywell Health.