Coke and diet coke contain caffeine, which can be problematic for those looking to cut down. To understand how much caffeine is in coke and diet coke, you need to know the size of the can or bottle.

Coca-Cola Classic — commonly simply referred to as Coke — and Diet Coke are popular beverages around the world.

However, soft drink consumption has been associated with many health concerns, ranging from weight gain to high blood sugar (1, 2).

Not only that, but Coke and Diet Coke also contain a hearty dose of caffeine. This article compares the caffeine contents of Coke, Diet Coke, and other beverages and tells you how it could affect your health.

Caffeine is a naturally-occurring chemical that acts as a central nervous system stimulant, enhancing alertness and fighting off fatigue.

It can be found in the leaves, seeds and fruits of many plants and is especially prevalent in cocoa beans, tea leaves and coffee beans (3).

It’s also commonly added to many products, including soft drinks, energy drinks and certain over-the-counter medications.

Nowadays, caffeine tops the charts as one of the most commonly consumed ingredients around the world (4).

In fact, it’s estimated that 85% of the US population consumes at least one caffeinated beverage per day, with an average daily intake of 165 mg of caffeine.

While coffee accounts for the majority of caffeine intake across the board, carbonated soft drinks like Coke make up a high proportion of the intake in those younger than 18 (5).


Caffeine is a natural stimulant found in many products including coffee, soft drinks, energy drinks and over-the-counter medications. Soft drinks account for a higher proportion of the intake in people younger than 18.

The caffeine content of Coke products depends on several factors, including the serving size and type of drink (6):

7.5-ounce (222-ml) can12-ounce (355-ml) can20-ounce (591-ml) bottle
Coke21 mg caffeine32 mg caffeine53 mg caffeine
Diet Coke28 mg caffeine42 mg caffeine70 mg caffeine

Decaffeinated varieties, such as caffeine-free Coca-Cola, are also available for those looking to cut their caffeine intake.


Coke contains 32 mg of caffeine per 12-ounce (335-ml) serving. Diet Coke is higher in caffeine, with about 42 mg per 12 ounces (335 ml).

Ounce for ounce, the amounts of caffeine in Coke and Diet Coke are significantly lower than most other caffeinated beverages including energy drinks, coffee and green tea (4, 7, 8):

Serving sizeCaffeine content
Coke7.5 ounces (222 ml)21 mg
Diet Coke7.5 ounces (222 ml)28 mg
Green tea8 ounces (237 ml)35 mg
Energy drinks8.3 ounces (245 ml)77 mg
Coffee8 ounces (237 ml)95 mg

Keep in mind, however, that the caffeine content varies for these drinks based on different factors, including brand, ingredients and specific type of beverage.


Coke and Diet Coke are generally lower in caffeine than other caffeinated beverages, including energy drinks, coffee and tea.

Caffeine consumption can have several benefits for your health.

In particular, research shows that it may increase metabolism, improve exercise performance and boost alertness (9, 10, 11).

However, it can also come with negative side effects, especially for people who are sensitive to its effects.

Caffeine can be addictive, and some research indicates that genetic variations could cause people to respond differently to it (12, 13).

Caffeine intake has also been shown to affect mental health, with one study in 2,307 children associating increased caffeine consumption with higher levels of perceived anxiety and depression (14).

Excess intake can also cause other side effects, including headaches, high blood pressure and sleep disturbances (15, 16, 17).

Additionally, it’s recommended that women who are pregnant or breastfeeding limit their caffeine intake, as it may be linked to a higher risk of miscarriage and low birth weight (18, 19).


Caffeine consumption has been linked to improvements in metabolism, exercise performance and alertness. However, it can also be addictive and may cause a wide range of side effects in some people.

When consumed in moderation, caffeine can be used safely with minimal risk of side effects.

In fact, doses up to 400 mg daily are considered safe for most adults (20).

Ideally, though, it’s best to limit your intake to around 200 mg daily to reduce your risk of side effects.

For reference, this equals just two 8-ounce (237-ml) cups of coffee or around five 8-ounce (237-ml) cups of green tea.

However, you would need to drink more than six 12-ounce (355-ml) cans of Coke or four 12-ounce (355-ml) cans of Diet Coke per day to reach this amount.


400 mg of caffeine daily is considered safe for most adults, but cutting your intake to 200 mg daily can help reduce your risk of adverse side effects.

Coke and Diet Coke contain 32 and 42 mg of caffeine per 12 ounces (335 ml) respectively, which is lower than other caffeinated beverages like coffee, tea and energy drinks.

However, they’re often high in sugar and other unhealthy ingredients, so keep your intake to a minimum to promote better health.

Instead, opt for other natural sources of caffeine in moderation, such as coffee or tea, to maximize the potential health benefits.