Short answer: have a standard coffee (about 107 mg) at least 8.8 hours before bed, so by about 2:12 pm for an 11 pm bedtime, and keep your day under 400 mg. Enter your day below to get your own cut-off, a pre-workout dose range and how much caffeine is still in you at bedtime. Free, no sign-up.
Last updated:
| What | Rule used | Source |
|---|---|---|
| Last caffeine before bed | Standard coffee (~107 mg): 8.8 h before bed. Pre-workout (~217 mg): 13.2 h before bed. Smaller drinks use the 8.8 h rule (the cautious choice); doses in between are scaled between the two points. | Gardiner et al., Sleep Medicine Reviews, 2023 |
| Daily limit | 400 mg a day for healthy adults; 200 mg a day if pregnant or breastfeeding; single doses up to 200 mg. | EFSA |
| Before training | Research range 3–6 mg/kg, usually ~60 min before; we suggest staying within the 200 mg single-dose guidance. | ISSN position stand, 2021 |
| Left at bedtime | Each drink halves every half-life (average 4–6 h; 1.5–10 h between people). | ISSN position stand, 2021 |
| Caffeine per drink | Filter coffee 90 mg, espresso 80 mg, black tea 55 mg, green tea 38 mg, cola 37 mg, energy drink 80 mg (typical; brands vary). | EUFIC |
General information for healthy adults, not medical advice. Don't use caffeine powders or mix caffeine with alcohol. If you're under 18, pregnant, have a heart condition, high blood pressure, anxiety or sleep problems, or take medication, check with a doctor or pharmacist first.
This tool puts a few of the named techniques from Caffeine Leverage to work. Each line says how it relates to the tool.
See every technique in Caffeine Leverage →
For a standard cup (about 100 mg), a 2023 meta-analysis suggests at least 8.8 hours before bedtime. With an 11 pm bedtime that's about 2:12 pm. A strong pre-workout (about 200 mg+) needs about 13 hours.
For healthy adults, EFSA says up to 400 mg a day spread through the day raises no safety concerns, and single doses up to 200 mg. That's roughly 4 cups of filter coffee. Pregnant or breastfeeding: up to 200 mg a day.
Sports research uses 3–6 mg per kg of body weight about an hour before training, and as little as 2 mg/kg may help. Most people do well staying at or under 200 mg in one go.
Falling asleep isn't the whole story: studies find caffeine late in the day can cut total sleep and deep sleep even when you fall asleep fine. The calculator's cutoff is about protecting sleep quality, not just getting to sleep.
Caffeine's half-life in adults averages about 4 to 6 hours but can range from about 1.5 to 10 hours between people, so half of a 200 mg dose may still be in your system 5 hours later.
Typical amounts (EUFIC, based on EFSA data): filter or instant coffee 200 ml about 90 mg, espresso 60 ml about 80 mg, black tea 250 ml about 55 mg, green tea 250 ml about 38 mg, cola 355 ml about 37 mg, energy drink 250 ml about 80 mg. Brands vary a lot.