Life How much caffeine is dangerous? Here’s what to know before reaching for another cup. December 2, 2022January 3, 2023Clare Mulroy, USA TODAYComments Off on How much caffeine is dangerous? Here’s what to know before reaching for another cup. The recommended limit for adult daily caffeine intake is 400 milligrams, or about four cups of coffee. Children under 12 should not consume caffeine.