Does Diet Coke or Coke 0 Have More Caffeine?

November 14, 2025 •

2 min read

According to The Coca-Cola Company, a 12-ounce can of Diet Coke contains 46 milligrams of caffeine, while the same size can of Coke Zero Sugar has 34 milligrams. This means Diet Coke contains approximately 35% more caffeine than Coke Zero.

Quick Summary

This article provides a direct comparison of the caffeine content in Diet Coke and Coke Zero Sugar, explaining which beverage contains more. It also covers other key differences, such as ingredients, flavor profiles, and nutritional details, to help inform your beverage choice.

Key Points

Diet Coke has more caffeine: A 12 oz can of Diet Coke contains 46 mg of caffeine, while Coke Zero Sugar has 34 mg.
Different sweetener blends: Diet Coke is sweetened only with aspartame, while Coke Zero uses a mix of aspartame and acesulfame potassium (Ace-K).
Distinct flavor profiles: Coke Zero is designed to taste more like classic Coca-Cola, whereas Diet Coke has a lighter, unique flavor.
Similar nutritional impact: Both beverages are sugar-free and calorie-free, making them nutritionally comparable despite minor ingredient variations.
Moderation is key: Health experts advise moderate consumption of all soft drinks, including those with artificial sweeteners, as neither beverage is a nutritional health food.
Personal preference matters most: The main deciding factor between the two beverages comes down to which flavor you prefer.

Diet Coke vs. Coke Zero: The Caffeine and Beyond

For many, a can of diet soda provides a satisfying dose of flavor and a quick energy boost without the added calories and sugar. But when comparing Diet Coke and Coke Zero Sugar, the differences go beyond taste. The caffeine content, while not wildly different, is one key area where the two beverages diverge, with Diet Coke offering a slightly more potent kick. Understanding these distinctions can help you choose the right drink for your preferences and health goals.

The Direct Comparison: Caffeine Content

Diet Coke contains 46 milligrams of caffeine per 12-ounce can, while Coke Zero Sugar contains 34 milligrams in the same serving size. This difference is a result of their unique formulations, designed to appeal to different tastes. Coke Zero was specifically created to taste more like classic Coca-Cola, which contains 34 mg of caffeine per 12 oz can. Diet Coke, introduced earlier, has a distinct, lighter flavor profile.

Beyond Caffeine: Other Key Differences

Beyond caffeine, Diet Coke and Coke Zero also differ in their artificial sweeteners and other ingredients, contributing to their distinct flavors and subtle nutritional variations.

Sweetener Profiles

Diet Coke: Sweetened exclusively with aspartame.
Coke Zero Sugar: Uses a blend of aspartame and acesulfame potassium (Ace-K).

Flavor Profiles

Diet Coke: Has a lighter, slightly citrusy taste.
Coke Zero Sugar: Tastes closer to classic Coca-Cola.

Nutritional Considerations Both beverages are calorie and sugar-free. However, they contain different levels of ingredients like phosphoric acid and potassium citrate, which contribute to their unique tastes and have been subject to health discussions regarding potential long-term effects of high consumption.

Comparison Table: Diet Coke vs. Coke Zero


Feature	Diet Coke (12 fl oz can)	Coke Zero Sugar (12 fl oz can)
Caffeine	46 mg	34 mg
Sweeteners	Aspartame only	Aspartame and Acesulfame Potassium (Ace-K)
Taste Profile	Distinct, lighter, with citrus notes	Closer to classic Coca-Cola
Potassium Citrate	No	Yes
Calories	0	0
Sugar	0g	0g

Health Considerations for Your Choice

The caffeine difference is generally minor for most people. The recommended daily caffeine intake for adults is up to 400 mg. Neither soda offers significant nutritional benefits and should be consumed in moderation as part of a balanced diet, as recommended by registered dietitians. The primary factor in choosing between them is often personal taste preference. Learn more about the differences from Coca-Cola.

Conclusion: Which One Will You Choose?

Diet Coke contains more caffeine than Coke Zero Sugar, with 46 mg versus 34 mg per 12-ounce can. Their differing artificial sweetener blends lead to distinct flavor profiles. While both are sugar-free and calorie-free, the choice between them largely depends on taste preference and individual caffeine sensitivity. Neither is a substitute for healthy hydration options like water, and moderation is advised.

Frequently Asked Questions

Diet Coke has more caffeine, with 46 milligrams per 12-ounce can. Coke Zero contains 34 milligrams of caffeine for the same serving size.

The difference in caffeine is due to their unique formulations. Coke Zero was designed to taste like classic Coca-Cola, which has the same 34 mg of caffeine, while Diet Coke was formulated with its own distinct flavor profile.

No, not all zero-sugar and diet sodas contain caffeine. Caffeine-free versions of both Diet Coke and Coke Zero are available, and some other soda brands are naturally caffeine-free.

No, while similar, the ingredients are not identical. Diet Coke is sweetened only with aspartame, but Coke Zero uses a blend of aspartame and acesulfame potassium (Ace-K).

Nutritionally, they are very similar, both being sugar-free and calorie-free. The choice is primarily based on taste. Neither offers significant health benefits, and both should be consumed in moderation.

No, the flavor profiles are different. Coke Zero is formulated to taste more like classic Coca-Cola, while Diet Coke has a lighter, different flavor.

For most healthy adults, the recommended daily caffeine limit is up to 400 milligrams. This means a can of either Diet Coke or Coke Zero is well within safe consumption limits.