Hours Worked Calculator
The arithmetic of a shift is subtraction, and it still goes wrong regularly — because the clock is base sixty, because the break may or may not be paid, and because a night shift finishes on a different day from the one it started. This handles all three and gives the answer in the decimal hours payroll wants.
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The break is where the disagreements start
Whether a break is paid is a matter of law in some places and of contract in others, and the two often disagree with what actually happens. In the United States, short breaks of five to twenty minutes are generally treated as paid working time under federal rules, while a genuine meal break of thirty minutes or more can be unpaid — but only if you are properly relieved of duty. Eating at your desk while answering the phone is not a break, and time spent that way is working time whatever the rota says.
That distinction is worth being precise about, because it is the single most common way hours quietly disappear. A thirty-minute lunch deducted every day but regularly interrupted is around two and a half hours a week.
Shifts that cross midnight
A finish time earlier than the start is read here as the next day, so 22:00 to 06:00 gives eight hours rather than a negative number. It is worth checking how your own timekeeping system handles this, since some quietly produce sixteen hours instead, and the correction is easier to make in the same week than three months later.
Work before and after the shift
Time spent on tasks that are integral to the job counts, even outside the rostered hours: starting up systems, mandatory handovers, putting on required protective equipment. Ten minutes of setup before every shift is roughly forty hours a year, which is a working week. Whether it appears on your timesheet depends on whether you write it down.
The weekly figure is the one that matters for overtime
Overtime in the United States is calculated on hours worked in a week, not in a day: over forty in a week attracts the premium, and a twelve-hour day inside a thirty-six-hour week generally does not. Several states, California among them, add a daily threshold on top of that. The weekly total above is the number to check against your own rules.
Keep your own record
Employers are required to keep accurate time records, and most do. Where a dispute arises, though, the person with a contemporaneous note of when they started and finished is in a far stronger position than the person relying on memory. A line in a notebook at the end of each shift is enough.
Frequently asked questions
How do I calculate hours worked?
Subtract the start time from the finish time, then take off any unpaid break. Convert to decimal hours for pay: 7 hours 45 minutes is 7.75.
Does my lunch break count as work?
A genuine meal break of thirty minutes or more where you are relieved of duty can be unpaid. Short breaks, and any break you spend working, count as paid time under US federal rules.
How do I work out a night shift that crosses midnight?
Treat the finish as falling on the next day. From 22:00 to 06:00 is eight hours: two hours to midnight and six after it. This calculator does that automatically when the finish is earlier than the start.
When does overtime start?
Under US federal law, after forty hours in a week. Some states add a daily threshold as well, so check both.
Should time spent setting up count?
If the task is integral to your job and required, generally yes. It adds up faster than people expect, so it is worth recording.