When to stop drinking instant coffee
Instant coffee · 8 oz holds about 62 mg of caffeine. That's 0.7× an 8-oz brewed coffee — #56 of 78 drinks on this site, and about 16% of the 400 mg daily ceiling. Pick your bedtime and sensitivity; the cell is the clock time your last one starts — computed with a 5 h average half-life, and the calculator above adjusts live.
Finish your last one by
—
Your 62 mg over the next 16 hours
| Bedtime | Sensitive · 25 mg | Standard · 50 mg | Tolerant · 100 mg |
|---|---|---|---|
| 10:00 PM | 3:27 PM | 8:27 PM | 10:00 PM |
| 11:00 PM | 4:27 PM | 9:27 PM | 11:00 PM |
| 12:00 AM | 5:27 PM | 10:27 PM | 12:00 AM |
Source — USDA FoodData Central (SR Legacy 174130), checked 2026-10-13. 26 mg per 100 g × 237 g.
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Common questions
When should I stop drinking instant coffee before bed?
For a 23:00 bedtime at standard sensitivity (50 mg bedtime limit), finish your last instant coffee by 9:27 PM. Sensitive readers should shift earlier; tolerant readers later.
Why do the times differ so much between people?
Caffeine half-life ranges 1.5–9.5 h across healthy adults, and dose differs by drink. The same can that clears a fast metabolizer by dinner can still be 50 mg in a slow one at midnight.
Method
Cutoff = bedtime − T½ × log₂(dose ÷ limit), base T½ 5 h, limits 25/50/100 mg. Every cell is computed, not quoted — the cutoff calculator applies the same formula with your metabolism factors.