Calculating time between two clock times
To find how long something lasted, convert both times to minutes after midnight and subtract. 9:00 AM is 540 minutes and 5:30 PM is 1,050 minutes, so the difference is 510 minutes, or 8 hours 30 minutes. Subtract a 30-minute unpaid lunch and the paid time is exactly 8 hours. The calculator uses a 24-hour clock internally, but your browser shows the time input in whatever format your device uses, so you can enter AM and PM times normally.
Overnight shifts
If the end time is earlier than the start time, the calculator assumes the period crossed midnight and adds 24 hours. A night shift from 10:00 PM to 6:30 AM is 8 hours 30 minutes. This works for any period up to 24 hours. For longer spans across multiple days, such as a 36-hour event, use the date difference calculator to count the days and add the hours separately.
Decimal hours for timesheets and payroll
Payroll systems and invoices usually need hours as a decimal rather than hours and minutes. To convert, divide the minutes by 60: 15 minutes is 0.25 hours, 20 minutes is 0.33, 30 minutes is 0.5 and 45 minutes is 0.75. So 7 hours 45 minutes is 7.75 hours, not 7.45, a common and costly mistake. The calculator shows decimal hours to two places, and if you enter an hourly rate it multiplies them to show the pay for the shift. Some employers round time to the nearest quarter hour or six minutes; check your workplace policy, as rounding rules must be applied fairly under US labor law.
Breaks and overtime
In the US, federal law does not require meal breaks for adults, but short rest breaks of 5 to 20 minutes must be paid if the employer offers them, while genuine meal breaks of 30 minutes or more where the worker is fully relieved of duty can be unpaid. Several states, including California, require meal and rest breaks. Under the Fair Labor Standards Act, non-exempt employees must be paid 1.5 times their regular rate for hours over 40 in a workweek, and some states also have daily overtime rules. Add up each day’s decimal hours across the week to check whether overtime applies. Freelancers can use the same method to track billable time for clients. Logging start and end times as you go, rather than reconstructing them at the end of the week, is the simplest way to keep timesheets accurate and avoid disputes about pay or invoices. Keep a copy of your records for at least a few years, as many employers and tax authorities expect.
Frequently asked questions
How do I calculate hours worked?
Subtract the start time from the end time, then subtract unpaid breaks. The calculator shows the result in hours and minutes and in decimal hours.
How do I convert minutes to decimal hours?
Divide by 60. For example, 45 minutes is 0.75 hours.
Does it work for overnight shifts?
Yes. If the end time is earlier than the start time, it assumes the shift crossed midnight.
What is 8:30 to 5:00 in hours?
8 hours 30 minutes, or 8 hours with a 30-minute unpaid lunch.