Diet Mountain Dew contains approximately 54 to 55 milligrams of caffeine per 12 fluid ounce (355 ml) can. This caffeine content is similar to that of regular Mountain Dew, which also has about 55 mg per 12 oz serving
. To put it in perspective, this amount is moderate compared to other caffeinated beverages: it's about half the caffeine found in an 8-ounce cup of coffee (which typically has 80-100 mg), and slightly more than a can of Coca- Cola (around 34-39 mg)
. There is also a caffeine-free version of Diet Mountain Dew available, but it is not widely distributed
. In summary, a standard 12 oz can of Diet Mountain Dew contains about 54-55 mg of caffeine.
