When to stop drinking coffee

A simple way to find your caffeine cutoff time so your last cup does not cost you sleep.

The short answer

As a starting point, stop drinking caffeine at least 6 hours before bed. In one well-known study, caffeine taken 6 hours before sleep measurably reduced how long people slept, even when they did not notice an effect. If you are sensitive to caffeine, or you had a large or late dose, move that cutoff earlier (often 8 to 10 hours before bed). If you go to sleep at 11 pm, a 6-hour cutoff means no caffeine after about 5 pm.

Why the timing matters so much

Caffeine has a half-life of about 5 hours, so it clears slowly. A coffee at 2 pm can still have a real amount active at 11 pm. The alert feeling fades within a few hours, which is why people assume they are fine, but the caffeine in your bloodstream is what lightens your sleep. For the full picture, see how long caffeine lasts.

How to find your cutoff time

1. Pick your bedtime. The time you actually want to be asleep.
2. Count back at least 6 hours. That is your starting cutoff.
3. Adjust for sensitivity and dose. Caffeine-sensitive, or a big afternoon cold brew? Move it earlier. Tolerate caffeine well and drink small amounts? Six hours may be plenty.
4. Check what is left at bedtime. Use the caffeine half-life calculator to confirm only a small amount remains when you go to bed, then fine-tune.

Example cutoffs by bedtime

Using a 6-hour starting rule (move earlier if you are sensitive):

What affects your personal cutoff

• Dose: a larger last drink leaves more caffeine at bedtime.
• Sensitivity and genetics: some people clear caffeine much more slowly.
• Pregnancy, nursing, liver or kidney conditions, and some medications: these can lengthen how long caffeine stays, so a much earlier cutoff is wise. Talk to a doctor.
• Smoking: tends to clear caffeine faster.

Because everyone is different, treat a cutoff as a personal experiment, not a rule. Estimates here are population averages for reference only, not medical advice.

For reference only, not medical advice. Caffeine 6 hours before bed reduced sleep in Drake et al., Journal of Clinical Sleep Medicine, 2013; half-life per the Institute of Medicine, Pharmacology of Caffeine (NCBI). See our Medical Disclaimer.

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