Hours Calculator

What the hours calculator does

You clocked in, you clocked out, and now you need to know how long you actually worked. That is this tool. You give it a start time and an end time, and it tells you the hours and minutes between them. If you took an unpaid break, you can knock that off too, so what you get back is real working time, not just the gap between the two clocks.

It hands you the answer three ways: as hours and minutes, as a total number of minutes, and as decimal hours, which is the form a timesheet or payroll system usually wants.

How to use it

1. Start Time. When the shift began.
2. End Time. When it finished.
3. Break Time (minutes). Optional. The total unpaid break to subtract, in minutes. Leave it blank if there was none.

Press Calculate for the total, or Reset to clear the boxes.

How the hours are worked out

It is the kind of sum that is easy to get a little wrong by hand, which is the whole reason to let the tool do it. It works out the gap between the two times in minutes, takes off your break minutes, then turns what is left back into hours and minutes, and also into decimal hours. So an eight and a half hour gap with a thirty minute lunch comes out as eight hours of paid time. If your end time reads earlier than your start time, it assumes the shift ran past midnight into the next day, which the next section covers.

An example with real numbers

Say you started at 9:00, finished at 17:30, and took a 30 minute lunch.

• From 9:00 to 17:30 is 8 hours 30 minutes, which is 510 minutes.
• Take off the 30 minute break: 510 minus 30 is 480 minutes.
• That is 8 hours 0 minutes, or 8.00 in decimal hours.

Without the break it would have been 8 hours 30 minutes, which is 8.5 in decimal. The break is what turns the clock-to-clock time into paid time.

Decimal hours, and why payroll wants them

That decimal figure is worth understanding, because it is the one most pay systems actually use. The reason is simple multiplication. To work out pay, you multiply hours by a rate, and you cannot cleanly multiply "8 hours 30 minutes" by an hourly rate, but you can multiply 8.5. So minutes get turned into a fraction of an hour by dividing by 60. The common ones are worth memorising: 15 minutes is 0.25, 30 minutes is 0.5, and 45 minutes is 0.75. So 7 hours 45 minutes is 7.75 hours, and at a given rate that is one easy sum away from the pay.

Shifts that cross midnight

Night shifts are where hand calculations fall apart, and where this tool quietly saves you. If you start at 22:00 and finish at 06:00, the end time looks earlier than the start, and a naive subtraction would give you a negative answer. The calculator spots that the finish must be on the next day and adds the missing hours, so that shift correctly reads as 8 hours. You just enter the times exactly as they appear on your timesheet and let it sort out the date change.

Questions people ask

How do I turn hours and minutes into decimal?

Divide the minutes by 60 and add them to the hours. So 8 hours 15 minutes is 8 plus 15 divided by 60, which is 8.25. The tool shows you the decimal figure automatically.

Does it handle overnight shifts?

Yes. When the end time is earlier than the start time, it treats the shift as running into the next day and adds the hours across midnight, so you get the right total instead of a negative one.

Does it take the break off automatically?

Yes, if you enter one. Put your total unpaid break in the minutes box and it subtracts it. A typical case is a 9 to 5 with an hour lunch, which is 7 paid hours rather than 8.

Does it know about daylight saving time?

No, it does pure clock-time arithmetic, so it does not adjust for the one day a year that is short an hour or the one that is long one. Most payroll is based on scheduled time anyway, so for a timesheet the clock-time answer is usually the one you want.