Hours Calculator

Formula

Total Hours = (End Time - Start Time) - Break Duration

Calculates hours worked by subtracting start time from end time, then deducting break duration. Handles overnight shifts (end time before start time) by adding 24 hours. Converts to decimal hours for payroll: minutes / 60.

Worked Examples

Example 1: Standard day shift with an unpaid lunch

Problem:Clock in at 09:00, clock out at 17:30, with a 45 minute unpaid break.

Solution:Convert both times to minutes past midnight: 09:00 = 9 x 60 = 540, and 17:30 = 17 x 60 + 30 = 1050. Elapsed clock time is 1050 - 540 = 510 minutes. Subtract the break: 510 - 45 = 465 minutes. Split that back into hours and minutes: 465 / 60 = 7 remainder 45. Decimal hours for payroll: 465 / 60 = 7.75.

Result:7h 45m worked = 7.75 decimal hours = 465 minutes

Example 2: Overnight shift that crosses midnight

Problem:Clock in at 22:15, clock out at 06:45 the next morning, with a 30 minute unpaid break.

Solution:In minutes past midnight, 22:15 = 1335 and 06:45 = 405. The raw subtraction is 405 - 1335 = -930, and removing the break gives -960, which is negative because the shift wrapped past midnight. Add one full day of 24 x 60 = 1440 minutes: -960 + 1440 = 480 minutes. That is 480 / 60 = 8 hours exactly, with no remaining minutes.

Result:8h 0m worked = 8.00 decimal hours = 480 minutes

Frequently Asked Questions

How does this handle a shift that crosses midnight?

If the end time is earlier on the clock than the start time, the raw subtraction comes out negative, and the calculator adds 1,440 minutes (one full day) to recover the real elapsed span. So 22:15 to 06:45 is read as 8 hours 30 minutes rather than a negative number. This assumes the shift is a single stretch shorter than 24 hours; for anything longer you need a date-aware calculation, not a time-of-day one.

Should I enter my lunch break as break minutes?

Enter it only if the break is unpaid and you were genuinely relieved of duty. Short rest breaks, typically under 20 minutes, are usually treated as paid working time and should be left out of the break field. A bona fide meal period where you are free from work is normally unpaid and belongs in the break field. If you eat at your desk while still covering the phones, that time is generally still hours worked.

How should the total be rounded for payroll?

Hours Calculator returns exact minutes and does not round. Many US employers round clock entries to the nearest quarter hour, a practice permitted under the Fair Labor Standards Act regulations as long as it is applied neutrally and does not, over time, systematically shortchange the employee. Rounding that always favors the employer is not allowed. Check your own jurisdiction and employment agreement, since some states and countries require exact-minute recording.

Background & Theory

Every clock time on this page is first flattened into a single count of minutes since midnight: 09:00 becomes 9 x 60 = 540, and 17:30 becomes 17 x 60 + 30 = 1050. Working in one unit removes the borrowing that makes base-60 subtraction error-prone by hand, where 17:15 minus 09:45 tempts people to answer 8 hours 30 minutes instead of the correct 7 hours 30. The unpaid break is subtracted in that same unit, and the remainder is converted back using integer division: 465 minutes becomes 465 / 60 = 7 whole hours with a remainder of 45 minutes. If the subtraction lands below zero, the shift crossed midnight, and adding 1,440 minutes for one full day recovers the true elapsed span. The decimal hours figure exists because payroll multiplies, and you cannot multiply a pay rate by 7 hours 45 minutes directly. Dividing total minutes by 60 gives 7.75, which times an hourly rate produces gross pay in a single step. Two traps catch people here: reading 7.45 as seven hours forty-five minutes, and assuming every tidy minute count yields a tidy decimal, when in fact only quarter hours land cleanly on .25, .50, and .75 while 10 minutes becomes a repeating 0.1667. This tool measures elapsed clock time and nothing else. It does not know whether your break is paid, whether the week has crossed an overtime threshold, or whether a night differential applies, so treat the output as raw duration that pay rules are applied to afterwards.

History

Counting hours worked only became an arithmetic problem once pay was detached from output. Under piecework rates and agricultural day wages, nobody totalled minutes. The change came with the factory, and the instrument that made it routine was the time clock: Willard Le Grand Bundy, a jeweller in Auburn, New York, patented a mechanical workman's time recorder in 1888. The Bundy Manufacturing Company he founded with his brother was among the firms merged in 1911 into the Computing-Tabulating-Recording Company, renamed IBM in 1924. Frederick Winslow Taylor pushed the same measuring instinct down to the individual task in The Principles of Scientific Management, published in 1911. Law then fixed the units. The Fair Labor Standards Act of 1938 set a federal minimum wage and required premium pay beyond forty hours in a workweek, which turned an accurate weekly total from an administrative convenience into a legal obligation. The implementing regulations at 29 CFR Part 785 define what counts as hours worked, and long-standing practice there permits rounding clock entries to the nearest quarter hour provided the rounding does not consistently favor the employer. Decimal hours became the standard reporting unit because mechanical and later electronic payroll equipment multiplied far more easily in base ten than in base sixty, and the convention has outlived the machines that produced it.