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Caffeine Intake Calculator

Estimate caffeine intake limits based on body weight.

Updated 2026-06-09Reading time: 3 min
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FAQs

How much caffeine is safe per day?

Up to ~400mg/day is generally considered safe for healthy adults. For performance, research supports 3–6mg per kg of bodyweight taken before training — the calculator scales this to your weight so you don't overshoot.

When should I take caffeine before a workout?

Plasma caffeine peaks roughly 30–60 minutes after ingestion, so taking it 30–60 minutes pre-training aligns the peak with your session. See our caffeine guide for the full evidence.

Why does caffeine stop working — and how do I protect my sleep?

Tolerance builds with daily use; occasional short breaks restore sensitivity. Caffeine's half-life is ~5–6 hours, so a late-afternoon dose still has meaningful levels in your system at bedtime — keep a cutoff of at least 8 hours before sleep.