Caffeine Intake Calculator

Total your daily caffeine from coffee, tea, energy drinks, and soda, compare against the 400 mg safe limit, and see when to stop for bedtime.

Espresso shots (75 mg each)

Brewed coffee cups, 240 ml (95 mg each)

Instant coffee cups (60 mg each)

Tea cups, 240 ml (47 mg each)

Energy drinks, 250 ml can (80 mg each)

Cola sodas, 355 ml (34 mg each)

Hour of day of last caffeine (0–24)

Bedtime (hour of day, e.g. 23)

Body weight (kg, for per-kg dose)

Total caffeine today

237

Breakdown

% of 400 mg daily limit: 59.30
mg per kg body weight: 3.39
Safe single dose for your weight (3 mg/kg): 210
Headroom before 400 mg: 163
From coffee: 190
From tea/energy/soda: 47
Still in system at bedtime (mg): 78.20
Hours to drop below 20 mg: 17.80
Latest caffeine hour for clean sleep: 5.20

Last updated: 2026-09-04

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FAQ

How much caffeine is safe per day?

For healthy adults, 400 mg a day is the widely cited safe ceiling — about four brewed coffees. Pregnant people are advised to stay under 200 mg, and teens under 2.5 mg per kg of body weight.

How long does caffeine last?

Caffeine's half-life averages five hours, ranging from two to ten depending on genetics, smoking, and pregnancy. Two brewed coffees at 3 pm still leave roughly 50 mg circulating at an 11 pm bedtime.

When should I stop drinking coffee?

Most sleep studies find measurable disruption while more than about 20 mg remains. For a 23:00 bedtime and typical metabolism, that means a last cup around noon — earlier than most people guess.

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