Caffeine Half-Life Calculator
Find out when your coffee leaves your system so you can sleep.
- Section
- Health & Vitality
- Reviewed
- Your data
- Stays local
1 Protocol
Hours
:
Mins
Clearance Timeline
After 5 Hours
7:00 PM
100 mg left
After 10 Hours
12:00 AM
50 mg left
Safe to Sleep
12:00 AM
< 50 mg
Method and basis
How the figure above is derived, and when not to act on it.
The 5-Hour Rule
The average half-life of caffeine is 5-6 hours.- If you drink 200mg at 4 PM (Double Espresso) ->
- At 9 PM, you still have 100mg in your blood.
- At 2 AM, you still have 50mg.
☕ Caffeine Metabolism Timeline (200mg Dose)
| Time Elapsed | Caffeine in System | Physiological Effect |
|---|---|---|
| 0 mins | 0 mg | Absorption begins |
| 45 mins | 200 mg (Peak) | Max Alertness / Jitters |
| 3 Hours | 130 mg | Focus remains high |
| 5 Hours (Half-Life)** | **100 mg | Effect fades, but still present |
| 10 Hours | 50 mg | Can inhibit deep sleep |
| 12 Hours | 25 mg | Trace amounts |
Strategy
Stop caffeine intake 8-10 hours before bed to ensure deep sleep quality (adenosine receptor availability).WinSport Editorial & Research Standards
All formulas and reference values used in this tool are sourced from peer-reviewed scientific literature and validated clinical guidelines. Our research team continuously audits each calculator for accuracy and updates methodology as new evidence emerges.
Read the Science
Sports Science Articles- The Maths of Four Coffees: Why Caffeine Accumulates More Than You ThinkEach cup of coffee doesn't clear before the next one arrives. Caffeine accumulates across doses via half-life stacking. Here's the pharmacokinetics — and why it matters for sleep and performance.5 min read
- Coffee Before Training Will Dehydrate You — Except It Won'tArmstrong 2002 and Killer 2014 both confirmed coffee hydrates as well as water. The caffeine diuretic myth persists in sport — here's what the evidence actually shows.5 min read
- Caffeine Half-Life: Exactly How Long Caffeine Stays in Your System8 min read
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