Shift Worker Sleep Calculator

The Shift Worker Sleep Calculator estimates the main sleep window after a work shift and can include an optional pre-shift nap.

Enter the relevant clock times and durations, choose Calculate, then read the day labels, assumptions, and warnings before using the schedule.

• Plan main sleep after night shift.
• Review day labels for overnight shifts.
• Add an optional pre-shift nap estimate.

Arrive-home time equals shift end plus commute home. Main bedtime equals arrive-home time plus wind-down. Main wake time equals sleep onset plus target main sleep.

• Clock times are converted to minutes from midnight.
• Intermediate calculations may go below 0 or above 1,440 minutes so previous-day and next-day labels are preserved.
• Display format is applied only after the schedule is calculated.

The key assumptions are fall-asleep duration, target sleep duration or cycle duration, and the selected age reference when one is used.

Cycle boundaries are labeled as estimates. They are not presented as confirmed sleep-stage transitions.

For a 10:00 PM-6:00 AM shift, 30-minute commute home, 30-minute wind-down, 15-minute latency, and 7.5-hour target main sleep, arrive home is 6:30 AM, bedtime is 7:00 AM, sleep onset is 7:15 AM, and wake time is 2:45 PM.

The output is a schedule estimate. It does not treat shift-work disorder or remove fatigue risk.

Shift work and long hours can disrupt sleep timing and fatigue risk. Safety-critical concerns should be handled with professional or occupational-health guidance.

Use these limits when reading any NexaCalc sleep result.

• The calculator works with clock times and user-entered assumptions. It does not measure sleep stages.
• A 90-minute sleep cycle is a planning convention. Individual cycles vary across the night and across people.
• Results do not guarantee alertness, sleep quality, recovery, or safety.

Do not use this calculator to justify driving or safety-critical work while severely sleepy. It does not recommend medication, melatonin, caffeine dosing, or stimulants.

Rotating schedules can create multi-day conflicts. Use the timeline as a planning aid, not as proof that adaptation has occurred.

Night shifts often start on one calendar day and end on the next. The calculator uses forward duration logic so the arrive-home and sleep-window labels remain clear.

The optional nap is shown as a separate planning item. It is not treated as a medical countermeasure or a guarantee of alertness.

If the planned sleep window becomes too short before the next work period, treat that as a scheduling concern rather than a reason to ignore fatigue.

People in safety-critical roles should follow workplace fatigue policies and qualified guidance. NexaCalc does not clear anyone to drive or operate equipment.

• CDC/NIOSH: Training for Nurses on Shift Work and Long Work Hours, reviewed October 12, 2021. Source.
• Centers for Disease Control and Prevention: About Sleep, age-based sleep-duration table, reviewed May 15, 2024. Source.
• National Institute of Neurological Disorders and Stroke: Brain Basics, Understanding Sleep, reviewed February 25, 2025. Source.
• National Heart, Lung, and Blood Institute: Sleep Deprivation and Deficiency, updated March 24, 2022. Source.
• Watson NF, Badr MS, Belenky G, et al. Recommended amount of sleep for a healthy adult. Sleep, 2015. Source.

Sleep reference data reviewed against CDC/AASM/AAP/NIOSH source families on June 21, 2026.