कैफीन कैलकुलेटर.

Caffeine content varies by brand and brewing; general information, not medical advice. Everything is calculated in your browser; nothing you type is uploaded.

Each dose decays exponentially with a half-life of about 5 hours (adjustable). Limits follow EFSA and FDA guidance: 400 mg a day for adults, 200 mg when pregnant, 3 mg per kg for teenagers.

A coffee at 7:30, a double espresso at 13:00 and a cola at 16:00 add up to 255 mg; about 55 mg is still in your body at 23:00.