When to use this page
Use this guide when a shift starts late and finishes the next morning, or when someone wants to check whether an overnight total looks reasonable before entering it into a calculator.
Count forward into the next day
A night shift should be treated as time that continues past midnight. If a worker starts at 10:00 PM and ends at 6:00 AM, the shift is 8 hours, not a negative difference. The next-day finish is what makes night shift math different from a regular daytime shift.
Once that overnight rule is clear, the rest of the calculation becomes much easier.