Is coffee at 3pm too late?
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Not if it’s one 8 oz cup. Drink it at 3pm and about 35 mg is still in you at an 11pm bedtime, about what a can of Coke has. A 16 oz cup at 3pm leaves about 70 mg, twice as much.
The 3pm coffee gets blamed for a lot of bad nights, and “no coffee after 2pm” is a common rule. For a small cup, the rule is stricter than it needs to be. For a big one, or an energy drink, it isn’t strict enough.
We think one small 3pm cup is fine for most people. Make it the small size, make it your last one, and keep the big cups for the morning. If it’s a 16 oz, or you’ve already had two, move it to lunch.
What a 3pm drink leaves at 11pm
| Drink at 3pm | Caffeine | Left at 11pm |
|---|---|---|
| Black tea, 8 oz | 47 mg | about 17 mg |
| Single espresso | 63 mg | about 23 mg |
| Red Bull, 8.4 oz | 80 mg | about 29 mg |
| Coffee, 8 oz | 95 mg | about 35 mg |
| Monster, 16 oz | 160 mg | about 59 mg |
| Coffee, 16 oz | 190 mg | about 70 mg |
| CELSIUS, 12 oz | 200 mg | about 73 mg |
| Pre-workout scoop, average | 254 mg | about 93 mg |
These use the average half-life of 5 hours. If yours is 3 hours, the 8 oz cup leaves about 18 mg, and if it’s 6 hours, about 41 mg.
Why one small cup is fine
In a 2025 trial, 23 young men had 100 mg of caffeine, a bit more than an 8 oz coffee, at 4 hours before bed, and their sleep showed nothing measurable. That dose leaves about 64 mg at bedtime. An 8 oz coffee at 3pm leaves about half of that by 11pm.
The same trial found 400 mg still cut about 21 minutes of deep sleep when it was taken 12 hours before bed. That’s the difference between a small 3pm cup and a big one. The dose changes the answer more than the hour.
If you already had a morning coffee
Caffeine stacks. An 8 oz coffee at 8am still leaves about 13 mg at 11pm, so with a second 8 oz at 3pm you’d fall asleep with about 48 mg in you. That’s just over the lower of our two bedtime lines (40 mg) and well under the higher one (80 mg). If your nights are fine, there’s nothing to change. If you wake up tired, make the 3pm cup a tea or a decaf for two weeks and see.
If your bedtime is different
The same 8 oz cup at 3pm leaves about 40 mg at 10pm and about 30 mg at midnight. The cutoff clock below starts with an 8 oz coffee at 8am and a 16 oz at 3pm, so you can see the difference a smaller second cup makes. The quiz works out your own latest time.
When should I stop?
When you fall asleep at 11:00pm
83 mgA measured cost
You'll fall asleep with about a cup of coffee in you.
- Brewed coffee, 8 oz95 mg
Brewed coffee, 16 oz190 mg
Your last drink, a 16 oz coffee at 3:00pm
- Under 40 mg at sleep
- by 8:10am
- Under 80 mg
- by 2:45pm
The full clock, with the band, 3am and the table by drink.
8 sources
- USDA FoodData Central, SR Legacy: brewed coffee (171890), espresso (171891), brewed black tea (173227) and brewed green tea (171917)fdc.nal.usda.gov
- The Coca-Cola Company, What is caffeine?coca-colacompany.com
- Gardiner C and others, Dose and timing effects of caffeine on subsequent sleep: a randomized clinical crossover trial, Sleep, 2025doi.org
- Antonio J and others, Common questions and misconceptions about caffeine supplementation: what does the scientific evidence really show? Journal of the International Society of Sports Nutrition, 2024doi.org
- Red Bull, How much caffeine is in a can of Red Bull? checked 2026-11-14redbull.com
- Monster Energy, 16 fl oz can, label photographed November 2025 (caffeine from all sources 160 mg per can), Open Food Facts 0070847811169, checked 2026-11-14world.openfoodfacts.org
- CELSIUS Sparkling Fantasy Vibe, 12 fl oz can, label photographed November 2025 (caffeine content 200 mg), Open Food Facts 0889392000597, checked 2026-11-14world.openfoodfacts.org
- Jagim AR, Harty PS, Camic CL, Common Ingredient Profiles of Multi-Ingredient Pre-Workout Supplements, Nutrients, 2019doi.org
