Timing Sleep
Sleep timing under constraints
Shift Worker Sleep Calculator
Built for night shifts, 12-hour shifts, rotating schedules, and anyone trying to wake up less wrecked.
Realistic buffers for falling asleep, waking up, winding down, and getting ready.
Planning tool only. Not medical advice.
Getting quality sleep as a shift worker is one of the hardest challenges in modern working life. Whether you work overnight in a hospital, pull 12-hour rotations in manufacturing, or juggle a schedule that flips between days and nights, your body's circadian rhythm is constantly fighting the clock. Most sleep advice assumes you go to bed at 10 PM and wake at 6 AM. That doesn't work when your shift ends at 7 AM and you need to be functional again by 11 PM.
This shift worker sleep calculator was built for people with irregular schedules. Instead of guessing when to sleep, you enter either the time you need to be awake and functional or the time you're getting into bed. The calculator works backward (or forward) from that anchor point, factoring in your personal buffers: how long it takes you to fall asleep, how much time you need to wake up fully, your wind-down routine, and how long you need to get ready before leaving the house.
The result is three clear sleep plan options based on 4, 5, or 6 full sleep cycles. Each plan shows you exactly when to start winding down, when to be in bed, when you'll likely fall asleep, and when to set your alarm. There's also a visual timeline so you can see the full sequence at a glance. You can copy a text summary to save or share your plan with a partner, and you can generate a share link that restores all your settings.
The calculator supports night shift, day shift, rotating shift, and custom shift patterns. Advanced options let you fine-tune every buffer, set constraints like "latest wake time" or "earliest bedtime," and adjust sleep cycle length. No accounts, no tracking, no ads. Just a practical tool for people who work when others sleep.
How it works
- Choose your planning style: set a wake deadline ("I must wake by...") or a bedtime ("I'm starting sleep at...").
- Select your shift pattern (Night, Day, Rotating, or Custom) to pre-fill sensible defaults.
- Adjust optional buffers: fall-asleep time, wake buffer, get-ready time, wind-down period, and sleep cycle length.
- Tap "Update Plan" to generate three sleep plan options (4, 5, or 6 full cycles) with a recommended timeline.
- Copy a text summary or share link to save your plan, or tap "Use Now" to start from the current moment.
Calculate your sleep plan
Enter your schedule details below to get a personalized sleep plan.
Advanced Options
Add your wake deadline or start time, then tap Update Plan. Use Now starts from the current moment.
Frequently Asked Questions
You enter either the time you need to be awake and functional, or the time you're getting into bed. The calculator works from that anchor point, adding your personal buffers (fall-asleep time, wake buffer, get-ready time, wind-down period) and generates three sleep plan options based on 4, 5, or 6 full sleep cycles.
A sleep cycle is a repeating pattern of lighter and deeper sleep stages, typically lasting about 90 minutes. Waking at the end of a cycle rather than in the middle helps you feel more alert and less groggy. For shift workers who have limited sleep windows, aligning wake times with cycle boundaries makes the most of the rest you get.
Yes. The calculator was specifically designed for night shift workers. Select the "Night" shift pattern, enter when you need to be functional (e.g., 10:30 PM for an 11 PM shift start), and the calculator will work backward to find your ideal bedtime, wind-down start, and wake time during the day.
With 12-hour shifts, your off-duty window is tight. Use the "I must wake by..." mode and set your functional time to at least 60-90 minutes before your shift starts. The calculator will show you whether 4, 5, or 6 cycles fit your window, so you can make a realistic choice rather than oversleeping or cutting rest too short.
Rotating shifts are the hardest on your body because your sleep window keeps changing. Use the "Rotating" preset as a starting point, then adjust your anchor time each time your schedule flips. The share link feature lets you save different configurations so you can quickly reload your plan for each rotation.
Buffers are the real minutes that surround actual sleep: "fall asleep buffer" is how long it takes you to drift off after lights out, "wake buffer" is time to fully wake up and orient yourself, "get ready time" covers showering, dressing, eating, and packing, and "wind-down time" is your pre-bed routine of dimming lights and stepping away from screens. These make your plan realistic instead of theoretical.
No. This is a planning tool, not medical guidance. It helps you structure your sleep window around your work schedule. If you're dealing with chronic insomnia, sleep disorders, or safety-critical fatigue, consider speaking with a clinician or sleep specialist.
No. There are no accounts, no sign-ups, and no data stored on any server. Everything runs in your browser. You can save your settings by copying the share link, which encodes your configuration in the URL so you can bookmark it or send it to someone else.