ShiftSync Calculator
Night Shift Caffeine Cutoff Calculator: When to Stop Coffee Before You Sleep
By Symone G. · Updated October 28, 2026
Many caffeine calculators are built around a night-time bedtime and a drink log. This one starts from your shift instead. Enter when your shift ends, and it counts back from when you will actually sleep.
Tonight's caffeine cutoff, plus your other 2 steps. No card needed.
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For most night shifts, stop caffeine about 8 hours before you plan to fall asleep. Caffeine's half-life is about 5 to 6 hours, and in one study a large dose (400 mg) taken 6 hours before bed still disrupted sleep. Finish at 7 AM and sleep by 8:30 AM? Your last caffeine is around 12:30 AM.
Caffeine cutoff by shift (examples)
Every time below is calculated with ShiftSync's 8-hour rule (stop caffeine 8 hours before your planned sleep start) and labelled as such. These are planning examples, not clinical guidance. Your own cutoff is the one the tool above gives you for your shift.
| Shift | Planned sleep | Stop caffeine by |
|---|---|---|
| 7 PM–7 AM | 8:00 AM | 12:00 AM (midnight) |
| 7 PM–7 AM | 8:30 AM | 12:30 AM |
| 11 PM–7 AM | 8:00 AM | 12:00 AM (one hour into the shift) |
| 6 PM–6 AM | 7:00 AM | 11:00 PM |
| 3 PM–11 PM | 12:30 AM | 4:30 PM |
| 7 PM–7 AM on Oct 31 → Nov 1, 2026 (13 hours) | 8:30 AM (standard time) | the first 1:30 AM |
If your cutoff lands before or right at clock-in
Some shifts leave almost no room for caffeine at all. On an 11 PM–7 AM shift with sleep planned at 8 AM, the cutoff is midnight, one hour in. Anything with caffeine has to come right at the start of the shift or before it. On nights like that, the plan matters more than the coffee. Build your alertness around light, movement and a break nap instead of a late top-up, and protect the sleep you are about to get. The wind-down side is covered in how to sleep after night shift.
The Nov 1 fall-back night
On Sunday, November 1, 2026, clocks fall back at 2:00 AM and the 1 AM hour happens twice (the NIST rule: daylight saving time ends on the first Sunday in November). Count the cutoff in real hours: 8 real hours before an 8:30 AM sleep start is the first 1:30 AM, not 12:30 AM. If you simply keep your usual clock time, you get an extra hour of margin built in. The tool above does the real-hours math for your zone. The fall-back guide plans the whole 13-hour night. Working the 13-hour night? Here's whether the extra hour is paid.
Why 8 hours? How caffeine half-life works
Caffeine starts working about 30 minutes after you drink it ( NIOSH puts the range at 15 to 45 minutes). Its half-life, the time your body takes to clear half of a dose, is about 5 to 6 hours. NIOSH also notes that caffeine can remain in your system much longer than that, and that a coffee near the end of a night shift can disrupt the morning's sleep.
In a 2013 study in the Journal of Clinical Sleep Medicine (Drake and colleagues), 400 mg of caffeine taken at bedtime, 3 hours before bed, or even 6 hours before bed each significantly disrupted sleep compared with placebo. The authors concluded that the results support avoiding substantial caffeine for at least 6 hours before bedtime. One caveat: the study tested 12 healthy normal sleepers with night-time bedtimes, not shift workers sleeping in the day.
Eight hours is ShiftSync's planning default. That's our reasoning, not a study finding. It adds margin beyond the 6-hour line because day sleep is lighter and more easily disrupted than night sleep, which is the same reason the guide to how to sleep after night shift treats the morning block as fragile. As an illustration (individual rates vary): at a 5.5-hour half-life, roughly a third of a dose is still in your system 8 hours later.
People clear caffeine at different speeds
Clearance varies between people. NIOSH notes caffeine “can remain in your system much longer” than the typical half-life, and the FDA notes wide variation in how sensitive people are to caffeine and how fast they eliminate it. If you are pregnant or taking medication, talk to a clinician about caffeine timing rather than relying on a general rule like this one.
How much caffeine is too much on a long night?
The FDA cites 400 mg per day as an amount not generally associated with negative effects for most adults, which is about two to three 12-oz cups of coffee. That is the FDA's general reference point, not a recommendation, and sensitivity varies widely. A longer shift is not a reason to raise your total. On the 13-hour fall-back night, spread what you would normally have across the longer night and keep the same cutoff. And check the labels on energy drinks and pre-workout, because the caffeine in them is easy to underestimate.
What counts as caffeine
Caffeine hides in more than coffee. The FDA lists products that may contain it, so check the label on:
- Coffee and espresso drinks, including decaf, which the FDA notes still has some caffeine
- Many teas, including black and green tea
- Caffeinated sodas and energy drinks
- Chocolate
- Pre-workout powders and other dietary supplements
- Energy or protein bars, ice cream and chewing gum with added caffeine
- Some over-the-counter medicines
The AASM view on caffeine for shift workers
The American Academy of Sleep Medicine's 2026 guideline for shift work disorder conditionally suggests caffeine before or during the night shift for excessive sleepiness, combined with bright light or a nap. The same guideline adds the remark that caffeine close to bedtime can disrupt sleep. Those recommendations are for adults with shift work disorder. They're context for the timing question, not a general prescription.
Quick answers
When should I stop drinking caffeine on night shift?
About 8 hours before you plan to fall asleep, which is ShiftSync's planning rule. For example, if you plan to fall asleep at 8:30 AM, stop caffeine by 12:30 AM.
How many hours before bed should I stop drinking coffee?
In a 2013 study, a 400 mg dose of caffeine taken even 6 hours before bed significantly disrupted sleep compared with placebo, and the authors concluded that substantial caffeine should be avoided for at least 6 hours before bed. ShiftSync uses 8 hours for day sleep, which is lighter and more easily disrupted, to add margin beyond that line.
What is caffeine's half-life?
About 5 to 6 hours, according to NIOSH. Half-life is the time your body takes to clear half of a dose, and NIOSH notes caffeine can remain in your system much longer than the half-life suggests. So a coffee late in a shift can still be partly working when you try to sleep.
Is coffee good for night shift?
Caffeine can aid alertness when it is used judiciously, per NIOSH, but timing matters: caffeine close to your sleep window can reduce the sleep you get afterward. The AASM's 2026 guideline for shift work disorder conditionally suggests caffeine before or during the night shift for excessive sleepiness, and notes that caffeine close to bedtime can disrupt sleep.
Does the cutoff change on the daylight saving night?
The rule does not change: count 8 real hours before your planned sleep. On the fall-back night of Nov 1, 2026, the 1 AM hour happens twice, so an 8:30 AM sleep time puts the cutoff at the first 1:30 AM. Using your usual clock time instead gives you an extra hour of margin. The fall-back guide has the full plan for that night.
Is this calculator medical advice?
No. ShiftSync gives general sleep-planning guidance. It is not medical advice and does not assess fitness for duty. Follow your employer's fatigue policies and talk to a clinician about sleep problems or supplements like melatonin.
Working nights as a nurse, in a warehouse, on EMS, as a trucker or on dispatch? Each role page runs this same engine on your roster. The anchor sleep guide and the night shift sleep schedule calculator explainer go deeper on the rest of the plan.
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ShiftSync gives general sleep-planning guidance. It is not medical advice and does not assess fitness for duty. Follow your employer's fatigue policies and talk to a clinician about sleep problems or supplements like melatonin.