A coffee at four, chai at six, bed at eleven. It is an ordinary enough routine, but the caffeine from those afternoon cups may still be with you when you turn out the lights.
When should you stop drinking coffee before bed? Try finishing caffeinated drinks about 8–10 hours before your usual bedtime as a starting point, then adjust according to how you sleep. If you go to bed at 11 PM, that means trying your last cup between 1 PM and 3 PM. This window is informed by sleep research, rather than a guarantee that works for everyone. [1]
That last cup includes chai. Tea, coffee, energy drinks and some supplements all contribute caffeine, even when they serve different purposes in your day. [9]
Find your caffeine cutoff time
Start with the time you actually plan to sleep and work backward. For a regular evening bedtime, here is what an 8–10-hour gap looks like:
| Usual bedtime | 10 hours earlier | 8 hours earlier |
|---|---|---|
| 10 PM | 12 noon | 2 PM |
| 11 PM | 1 PM | 3 PM |
| 12 midnight | 2 PM | 4 PM |
| 1 AM | 3 PM | 5 PM |
Use these times to plan a change, not to decide that a later cup is harmless. If you struggle to fall asleep, wake often or feel unrefreshed, try the earlier end of the window and a smaller amount. A large caffeine dose may need a longer gap.
If you work nights, an afternoon cutoff will not make much sense. Use your planned sleep time instead. CDC guidance suggests taking caffeine near the beginning of a shift and stopping several hours before the shift ends. [3]
Why coffee can affect sleep after the boost wears off
During the day, a chemical called adenosine builds up and helps signal that it is time to rest. Caffeine blocks its action on brain cells, making you feel more awake. How quickly your body breaks down caffeine varies, partly because of genetics. [2]
You may stop noticing the lift from a cup before the caffeine has left your body. Falling asleep easily is not the whole test either: caffeine can affect the amount of sleep you get and how disrupted that sleep is. [5]
How long does caffeine stay in your system?
The CDC gives a typical caffeine half-life of about 5–6 hours, though it can be much longer in some people. A half-life is the time it takes for the amount in your body to fall by half. [3]
Imagine a drink containing 100 mg of caffeine at 2 PM. With a five-hour half-life, the amount remaining from that drink would look roughly like this:
| Time | Time since the drink | Caffeine remaining |
|---|---|---|
| 2 PM | Just consumed | 100 mg |
| 7 PM | 5 hours | 50 mg |
| Midnight | 10 hours | 25 mg |
This is a calculation to explain half-life, not a measurement of your metabolism. A second cup adds more caffeine. Even a ten-hour gap does not mean you are caffeine-free at bedtime.
What recent caffeine and sleep research tells us
A 2023 review of 24 studies found that caffeine reduced total sleep time by about 45 minutes on average. Its modelling estimated that a coffee containing 107 mg of caffeine would need to be consumed around 8.8 hours before bed to avoid reducing total sleep time. That helps explain the eight-to-ten-hour starting window, but the estimate cannot give each person an exact cutoff. [1]
A trial published in the 2025 issue of Sleep looked more closely at dose and timing. Twenty-three men who regularly consumed moderate amounts of caffeine received 100 mg or 400 mg test doses, taken 4, 8 or 12 hours before bed. The 100 mg dose produced no statistically significant sleep changes at those times. The 400 mg dose affected sleep even at the twelve-hour mark, with greater disruption closer to bedtime. [4]
The distinction matters: 400 mg was a single test dose, rather than a day's intake spread across several cups. The small trial also cannot establish that 100 mg four hours before bed is harmless for women, older adults or everyone sensitive to caffeine. [4]
A December 2025 meta-analysis combined 22 controlled crossover trials involving 956 participants. It found about 35 minutes less sleep on average, along with longer time to fall asleep and lower sleep efficiency. Both lower-dose and higher-dose groups showed effects on some sleep measures. [5] A 2026 population analysis also linked higher caffeine intake with short sleep, although its observational data and self-reported sleep cannot prove cause and effect. [6]
For your own routine, pay attention to both the clock and the amount in the cup. A small afternoon coffee and a large caffeine dose are different things.
Count the chai as well as the coffee
Morning filter coffee is easy to remember. The chai during a work break, or another cup after dinner, can slip out of the count. Adding milk or spices does not remove caffeine already present in the brewed drink.
The ICMR–NIN guidelines give the following estimates for 150 ml servings of brewed coffee, instant coffee and tea. The decaf figure comes from the FDA and uses a larger serving. [7], [8]
| Drink | Serving | Caffeine estimate |
|---|---|---|
| Brewed coffee | 150 ml | 80–120 mg |
| Instant coffee | 150 ml | 50–65 mg |
| Tea | 150 ml | 30–65 mg |
| Decaf coffee | About 240 ml | 2–15 mg |
These are reference values, not laboratory results for every cup of chai, South Indian filter coffee or Bermito coffee. The amount of tea or coffee you use, the recipe and the serving size can change the dose considerably. Use a product's caffeine information when it is available. [8]
Suppose two coffees contain 100 mg each and a later chai contains 50 mg. That hypothetical day's total is 250 mg. It may sit below a daily intake guideline, but the timing of the last drink can still matter for sleep.
Check cold brew carefully too. A concentrate and a ready-to-drink bottle can deliver very different amounts. Look at the dilution instructions, your portion and whether the label gives caffeine per serving or per bottle. A smooth taste does not tell you how much caffeine you are drinking.
Daily caffeine guidance for adults in India
The ICMR–NIN Dietary Guidelines for Indians 2024 advise moderation so that daily caffeine intake does not exceed 300 mg. The FDA gives 400 mg a day as an amount not generally associated with negative effects for most adults, while stressing that responses vary. Neither figure guarantees that your sleep will be unaffected. [7], [8]
Use the Indian guidance as your local reference and pay attention if a smaller amount affects your sleep or comfort. Count caffeine from all sources, including cola, energy drinks, supplements and relevant medicines. [9]
Try an earlier last cup for two weeks
You do not need a perfect caffeine calculation to begin noticing a pattern. A simple drink-and-sleep record can help:
- For the first few days, write down each caffeinated drink, its size and the time you have it. Note your bedtime, roughly how long you take to fall asleep and how rested you feel the next morning.
- During the following week, move your last caffeinated drink earlier, using the cutoff table as a starting point. Keep your sleep schedule as consistent as you reasonably can.
- If that does not help enough, try reducing the size or caffeine content of the last cup. Look for a pattern across several nights.
- After your cutoff, choose a caffeine-free drink or decaf if the small amount of remaining caffeine suits you. Check herbal blends: those containing black or green tea still contribute caffeine.
This is a practical observation, not a diagnostic test. If you drink several cups a day, reduce your intake gradually; suddenly stopping regular caffeine can cause headaches, drowsiness and difficulty concentrating. [9]
If you are pregnant, breastfeeding, taking medicines that may interact with caffeine or managing a sleep condition, ask your healthcare professional for advice suited to you. The adult figures above are not targets for children or teenagers. Persistent sleep problems deserve attention even after you change your caffeine routine. [9]
Keep the cup you enjoy, and give it a place earlier in the day. For help making that cup taste better, read our guide to brewing coffee at home.
Frequently asked questions
Can I drink coffee at 4 PM?
It depends on your bedtime, the dose and your response. If you sleep at 11 PM, a 4 PM coffee leaves seven hours, outside the 8–10-hour starting window used here. Try moving it earlier if your sleep is affected. [1]
Does chai affect sleep?
Chai made with tea leaves contains caffeine, so include it when setting your cutoff. ICMR–NIN estimates 30–65 mg in a 150 ml serving of tea; your chai's recipe will influence the amount. [7]
Is decaf coffee completely caffeine-free?
No. The FDA reports about 2–15 mg in an 8-fluid-ounce cup, approximately 240 ml. If you react strongly to caffeine, that small amount may still be worth considering. [8]
Does cold brew contain less caffeine?
There is no single answer for all cold brew. The recipe, concentration and portion matter. Check the label where available, especially for concentrates and bottles containing more than one serving.
Can coffee affect sleep even if I fall asleep easily?
Yes. The dose-and-timing trial found that participants did not always notice the sleep changes shown by measurement. Falling asleep easily does not rule out effects on the rest of the night. [4]
Sources and further reading
Research checked on 1 October 2026. This article provides general information about coffee and caffeine.
- Gardiner and colleagues 2023. The effect of caffeine on subsequent sleep. Systematic review and meta-analysis of 24 studies. Sleep Medicine Reviews 69 101764. Read source.
- US National Institutes of Health 2020. Tired or Wired. Caffeine and your brain. Read source.
- CDC NIOSH. Training for nurses on shift work and long work hours. Caffeine half-life. Timing caffeine around shifts.
- Gardiner and colleagues 2025. Dose and timing effects of caffeine on subsequent sleep. Randomized clinical crossover trial. Sleep 48 4 zsae230. Published online in October 2024. Read source.
- Chang and colleagues December 2025. Age and dose specific effects of caffeine on sleep. Meta-analysis of controlled crossover trials. Sleep Medicine 136 106874. Abstract available from the authors' institution. Read source.
- SLEEP Advances 2026. Evaluating the association between caffeine exposure and sleep duration and trouble sleeping in adults. Observational analysis of NHANES data. Read source.
- ICMR National Institute of Nutrition 2024. Dietary Guidelines for Indians. Tea and coffee guidance on printed page 91. Read source.
- US Food and Drug Administration. Spilling the Beans. How much caffeine is too much. Adult intake guidance, variable drink content and decaf caffeine. Read source.
- MedlinePlus National Library of Medicine. Caffeine. Withdrawal symptoms and circumstances requiring individual advice. Read source.
