Caffeine Calculator
Track daily caffeine against the 400 mg limit
Use this when you need a fast, accurate result — no sign-up, works entirely in your browser.
Total caffeine (mg)—
mg per kg body weight—
Vs. 400 mg daily limit—
Amount left after 5h—
How to Use
- Enter your details into the fields above.
- Click the calculate button to get your result instantly.
- Use the clear button to start a new calculation.
Example
- 70 kg, 2 coffees + 1 tea → 237 mg total (3.39 mg/kg); within the 400 mg daily limit; ≈ 119 mg left after 5 h
- 70 kg: 3 coffee + 1 tea + 1 soda → ≈ 366 mg caffeine (5.23 mg/kg); approaching the 400 mg daily limit
Formula
Typical caffeine per serving: coffee 95 mg, tea 47 mg, soda 34 mg, energy drink 80 mg. The FDA cites 400 mg/day as an amount not generally associated with negative effects for healthy adults. Caffeine has a half-life of about 5 hours, so roughly half remains after that time.
About Caffeine Calculator
Track daily caffeine against the 400 mg limit. This free online tool gives you fast, accurate results without registration or downloads.
Everything runs locally in your browser, so your data is never uploaded or stored — privacy first.
Frequently Asked Questions
Is this tool free to use? +
Yes, it is completely free with no registration or download required.
Is my data private? +
Yes. Everything is processed locally in your browser. Nothing is uploaded or stored on our servers.
Does it work on mobile? +
Yes, it works on any device — phone, tablet, or desktop.