Caffeine Safe Limit Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 27, 2026
Disclaimer: This calculator is provided for informational and educational purposes only and does not constitute financial, medical, legal, or other professional advice. Always consult a qualified professional before making decisions based on these results.
How caffeine limits are set
The FDA cites 400mg per day as an amount generally not associated with adverse effects in healthy adults. Some clinical guidelines further scale this per body weight, roughly 6mg per kilogram, capped at the general 400mg maximum regardless of weight.
Worked example
For a 70kg adult currently consuming 200mg of caffeine daily:
Weight-based = 70 x 6 = 420mg -> capped at 400 mg/day limit
200 / 400 x 100 = 50% of the limit consumed
| Source | Typical Caffeine |
|---|---|
| Brewed coffee (8 oz) | ~95 mg |
| Espresso shot | ~63 mg |
| Black tea (8 oz) | ~47 mg |
| Energy drink (8 oz) | ~80 mg |
Pregnant individuals and people with certain heart conditions are generally advised much lower limits by their doctor - this calculator reflects general adult population guidance only.