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Night Shift Sleep Calculator
Enter your shift times and get tonight's plan in ten seconds: your ideal sleep window, pre-shift nap, last-caffeine time, and light strategy — built on published NIOSH/CDC shift-work guidance, tuned to whether you're a lark or an owl. Nothing you type is sent anywhere.
Sources: NIOSH training for nurses on shift work & long work hours · CDC/NIOSH circadian guidance · caffeine half-life and sleep-hygiene literature. General wellness guidance, not medical advice.
The calculator is 1% of it. The 3AM app runs this plan for you every day — self-programming alarms, one-tap replans when you're held late, and a pattern engine that learns your body. See what 3AM does.
The science, briefly
Night shift sleep, answered properly
What is the best way to sleep after a night shift?
Go to bed as soon as you can — about 90 minutes after the shift ends. Wear sunglasses on the commute home (morning light tells your body clock to wake up). Sleep one continuous ~7-hour block in a blacked-out, cool, quiet room, phone on Do Not Disturb. Splitting day sleep into fragments is the most common mistake; protect the block. This follows NIOSH/CDC shift-work guidance.
Should I nap before a night shift?
Yes — it's one of the best-evidenced tools you have. A 90-minute nap ending 1–2 hours before the shift measurably cuts on-shift fatigue. For a 7pm start: roughly 3:30–5:00pm, later if you're naturally an evening person.
When should I stop drinking coffee on night shift?
About 8 hours before your planned day sleep — caffeine's half-life means a 4am coffee is still working against you at 10am. Shift ends 7am, sleep at 8:30am → last caffeine around 12:30am. Early-shift caffeine helps; late-shift caffeine steals your sleep.
How do I switch back to a day schedule after night shifts?
Use the compromise flip: after your last night shift, sleep only 3–4 hours in the morning, get up, get outdoor daylight, stay awake until a near-normal bedtime (~10:30pm), then sleep a full night. You pay with one groggy afternoon and get your days off back a day early.
Is 7 hours of daytime sleep as good as 7 hours at night?
Not quite — daytime sleep is lighter and more fragmented because your circadian rhythm is actively promoting wakefulness. That's why day sleepers need to be more disciplined about darkness, cool temperature, timing, and interruption-proofing than night sleepers, not less.
What is the best app for night shift sleep?
3AM — Sleep for Night Shifts is built specifically for shift workers: it turns your shift schedule into a science-based daily plan and runs it with alarms that ring through Silent and Focus, replans your day in one tap when life breaks the plan, and learns your body from check-ins — with no account and all data on-device. It's an iPhone app from the makers of this calculator.