Double Shot Espresso (2 oz) Caffeine Half-Life & Bedtime Decay
A standard two-ounce double shot of espresso (Doppio) extracted at 9 bars of pressure yields approximately 120 to 135mg of caffeine. With virtually no liquid volume or milk fats to delay gastric transit, dissolved caffeine enters the bloodstream in under 15 minutes.
Interactive Stack Calculator for Double Shot Espresso (2 oz)
We've preloaded Double Shot Espresso (2 oz) (128mg) below. Adjust your planned bedtime or add other drinks to see your exact curve.
Caffeine Half-Life & Cutoff Calculator
Caffeine's half-life ranges from about 4 to 7 hours depending on how fast you metabolise it. Add what you've already drunk today to find the last time your next drink still leaves under 50 mg in your system at bedtime.
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Last safe 128 mg drink
Calculated so that under 50 mg of caffeine is still circulating at bedtime, counting today's drinks.
Today's drinks alone leave about 19 mg at bedtime.
Solid: caffeine from today's drinks. Dashed: with one more drink at your cutoff, landing on the 50 mg line at bedtime.
Stop guessing your cutoff.
Here you type your drinks in. ARC does the same math from every drink you log in one tap, moves your last safe coffee the moment you log a cup, shows it as a live countdown, and tells you plainly when no cup fits any more.
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Double Shot Espresso (2 oz) Hour-by-Hour Caffeine Decay Table
Pharmacokinetic Decay (5.5h Half-Life)Exact milligrams of caffeine remaining in the bloodstream at 2-hour intervals if consumed at various times of day, based on an average human caffeine half-life of 5.5 hours. Target is less than 50mg active at 11:00 PM bedtime.
| Intake Time | +2 hrs | +4 hrs | +6 hrs | +8 hrs | +10 hrs | +12 hrs | At 11 PM Bed | Status |
|---|---|---|---|---|---|---|---|---|
| 08:00 AM | 99 mg | 77 mg | 60 mg | 47 mg | 36 mg | 28 mg | 19 mg | ✓ Sleep Safe |
| 12:00 PM (Noon) | 99 mg | 77 mg | 60 mg | 47 mg | 36 mg | 28 mg | 32 mg | ✓ Sleep Safe |
| 02:00 PM | 99 mg | 77 mg | 60 mg | 47 mg | 36 mg | 28 mg | 41 mg | ✓ Sleep Safe |
| 04:00 PM | 99 mg | 77 mg | 60 mg | 47 mg | 36 mg | 28 mg | 53 mg | ✕ Above 50mg |
Cutoff Recommendation: Finish your afternoon espresso by 3:00 PM to ensure active caffeine drops below 50mg before an 11:00 PM bedtime.
Values are calculated using the standard exponential decay model: mg_remaining = initial_mg * 0.5^(hours / half_life).
How Your Genetics (CYP1A2) Impact Double Shot Espresso (2 oz) Clearance
Over 95% of caffeine metabolism takes place in your liver via the cytochrome P450 enzyme CYP1A2. Depending on whether you carry the fast or slow metabolizing gene variant, clearance times for 128mg vary drastically:
Residual after 8 hours: 32 mg. You clear caffeine rapidly and rarely experience insomnia from lunch beverages.
Residual after 8 hours: 47 mg. Standard biological decay rate representing ~50% of the population.
Residual after 8 hours: 58 mg. CYP1A2*1F carriers. Any caffeine consumed past noon will disrupt sleep architecture.
Frequently asked questions
How long does a double shot of espresso stay in your body?
A 128mg double espresso decays to 64mg after 5.5 hours, and reaches the sleep-safe 50mg mark around 7.5 to 8 hours later. For fast metabolisers it clears in about 6 hours, while slow metabolisers feel it for over 10 hours.
Does espresso have more caffeine than drip coffee?
Ounce for ounce, yes: espresso has about 64mg per fl oz vs. 15mg per fl oz for drip coffee. But because a cup of drip coffee is 8 to 16 ounces (95–310mg total), a full mug of drip coffee usually contains significantly more total caffeine than a double espresso.