Both Coke Zero Sugar and Diet Coke contain caffeine. However, the caffeine content is not the same in each soda. The table below shows a comparison of the caffeine in each beverage.
| Serving Size | Coke Zero Sugar – Caffeine (mg) | Diet Coke – Caffeine (mg) |
| 7.5 fl oz | 21 | 28 |
| 12 fl oz | 34 | 46 |
| 20 fl oz | 57 | 76 |
Ingredients
Caffeine is an added ingredient in Coke Zero Sugar and Diet Coke. Since it is added and not naturally occurring, caffeine is included in the ingredients list for each beverage.
Coca-Cola Zero Sugar – Carbonated Water, Caramel Color, Phosphoric Acid, Aspartame, Potassium Benzoate (To Protect Taste), Natural Flavors, Potassium Citrate, Acesulfame Potassium, Caffeine.
Diet Coke – Carbonated Water, Caramel Color, Aspartame, Phosphoric Acid, Potassium Benzoate (To Protect Taste), Natural Flavors, Citric Acid, Caffeine.
Caffeine Comparison
Coke Zero Sugar and Diet Coke have low to moderate caffeine levels for their 12-ounce serving sizes. Pepsi Zero Sugar is a good alternative if you are looking for more caffeine in your soda. However, if you are looking for no caffeine, Coke offers Caffeine Free Coke Zero Sugar and Diet Caffeine Free Coke.
| Beverage | Serving Size | Caffeine (mg) |
| Coke Zero | 12 fl oz | 34 |
| Diet Coke | 12 fl oz | 46 |
| Diet Pepsi | 12 fl oz | 35 |
| Pepsi Zero Sugar | 12 fl oz | 69 |
| Diet Dr Pepper | 12 fl oz | 41 |
| Coca-Cola Classic | 12 fl | 34 |
| MTN Dew | 12 fl oz | 54 |
| Diet MTN Dew | 12 fl oz | 54 |
| Pepsi | 12 fl oz | 38 |
| RC Cola | 12 fl oz | 43 |
| Red Bull | 12 fl oz | 114 |
| Monster Energy | 12 fl oz | 120 |
| Coffee | 12 fl oz | 136* |
Sources:
us.coca-cola.com
dietcoke.com
Coca-Cola Zero Image Credit – Rob Marquardt/flickr
