Hours Calculator
Enter a start time and end time to calculate total hours worked. Supports break deductions and overnight shifts.
Enter your start and end times, select a break duration, and optionally add your hourly wage to calculate total hours and earnings.
Disclaimer: The results provided by this tool are estimates for informational purposes only. Actual values may vary. Please verify important calculations independently.
How the hours math works
Under the hood, the hours calculator converts each time you enter into a number of minutes past midnight, then subtracts the start from the end to get the raw duration. When you type 9:15 AM, that becomes 555 minutes; 5:45 PM becomes 1065 minutes; the difference, 510 minutes, is divided by 60 to yield 8.5 decimal hours. Breaks are simply subtracted from that gross figure before the result is shown. Because the tool works in minutes rather than floating-point hours, it sidesteps the rounding errors that creep in when payroll software adds and subtracts fractions like 0.333 or 0.1666 repeatedly.
Overnight shifts are detected by comparing the two times: if the end time is numerically smaller than the start time, the calculator adds a full 1440 minutes — one day — to the end before subtracting. This correctly handles a 10 PM to 6 AM shift as 8 hours rather than negative 16. For earnings, the final decimal hours figure is multiplied by the hourly wage you enter, giving a gross total that ignores taxes, tips, and premium pay. The hours calculator aims to be transparent about every step so you can sanity-check it against your own arithmetic.
When decimal hours matter in practice
Decimal hours are the lingua franca of payroll. ADP, QuickBooks, Gusto, and virtually every time-clock system store work durations as decimals because multiplication by a wage is trivial: 7.5 times $22 is immediately $165, whereas 7 hours 30 minutes requires two operations and an understanding that the minutes segment is base-60, not base-100. This is why a 15-minute block is 0.25 hours, a 20-minute block is 0.333 hours, and a 45-minute block is 0.75 hours. Writing 7.30 when you mean 7 hours 30 minutes is a classic error that under-pays or over-pays by several dollars per week.
The hours calculator is most useful for freelancers invoicing clients, hourly employees double-checking a paycheck, students logging internship hours, and managers estimating labor costs before approving a shift swap. If your employer rounds clock-ins to the nearest quarter-hour, run the same shift through the calculator with your true times and then with the rounded times; the difference over a month is often larger than people expect. Wage rules and rounding policies vary by jurisdiction and employer, so treat the output as an informed estimate rather than a formal payroll statement.