How to Calculate Work Hours and Overtime

To calculate work hours, subtract the start time from the end time, then take off any unpaid break. From 9:00 AM to 5:30 PM is 8 hours 30 minutes; with a 30 minute lunch, that’s 8 hours worked. If a shift ends after midnight, add 24 hours to the end time first. For pay, turn minutes into decimal hours by dividing by 60.

The hours calculator does this for a single shift and for a full weekly timesheet, including overtime and pay. Here is how the maths works, so you can check a payslip or timesheet yourself.

Hours between two times

The easiest method is to convert both times to the 24 hour clock, then to minutes after midnight:

1. Start 8:45 AM = 08:45 = 8 × 60 + 45 = 525 minutes
2. End 5:15 PM = 17:15 = 17 × 60 + 15 = 1,035 minutes
3. 1,035 − 525 = 510 minutes = 8 hours 30 minutes

Working in the 24 hour clock avoids the most common mistake, which is mixing up AM and PM. If you need to switch formats, the 12 to 24 hour time converter helps.

Taking off breaks

Subtract unpaid breaks from the total. A 9 to 5 day is 8 hours on the clock but 7 hours of paid work with a 1 hour lunch. Whether breaks are paid depends on your employer and contract; short tea breaks are often paid, while lunch often isn’t. Check your contract or ask HR.

Night shifts that cross midnight

If the end time is earlier than the start time, the shift crossed midnight. Add 24 hours (1,440 minutes) to the end time before subtracting. A shift from 10:00 PM to 6:00 AM: 6:00 AM is 360 minutes, plus 1,440 = 1,800; 10:00 PM is 1,320 minutes; 1,800 − 1,320 = 480 minutes = 8 hours. The calculator spots this automatically.

Minutes to decimal hours

Payroll and timesheet software usually works in decimal hours, so 7 hours 30 minutes is 7.5, not 7.30. Divide the minutes by 60:

So 7 hours 45 minutes = 7.75 hours, and at Rs 600 an hour that’s 7.75 × 600 = Rs 4,650. Writing it as 7.45 would underpay by 18 minutes.

A weekly timesheet example

Here is a six-day week with different breaks each day:

If overtime starts after 40 hours a week, this person worked 5.25 hours of overtime. At an example rate of Rs 600 an hour, with overtime paid at 1.5 times, the week’s pay would be 40.00 × 600 + 5.25 × 900 = Rs 28,725. At double rate it would be Rs 30,300.

Overtime rules

Overtime rules vary by country, industry and contract. Some systems count overtime per day, some per week, and the extra rate may be 1.5 times, twice the normal rate, or time off in lieu.

In Pakistan, the Factories Act 1934 sets a 48 hour week for adult factory workers, and overtime beyond the limits is paid at twice the ordinary rate. Other workplaces such as shops, offices and establishments are covered by different, often provincial, laws, and your contract may set its own terms. The hours calculator lets you set the weekly limit (for example 48) and pays overtime at 1.5 times; if you’re owed double, add another half of your hourly rate for each overtime hour.

Related tools

To count the days in a pay period or between two dates, use days between dates. To see how many pay days are left this year, try the paydays calculator. And if you’re comparing working days for a deadline, our guide to business days explains how weekends and holidays are counted.

Frequently asked questions