To find a time duration, convert both clock times to minutes since midnight and subtract. If the end is earlier than the start, the span has crossed midnight, so add 24 hours (1440 minutes). The result converts cleanly: hours:minutes from the total minutes, decimal hours by dividing by 60 (handy for payroll), and total minutes or seconds for fine-grained needs. That single trick — minutes since midnight, with a midnight wraparound — covers day shifts, night shifts and everything between.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: minutes-since-midnight time arithmetic.
The time duration method
Turning each time into a single minute count removes the awkwardness of borrowing across the hour. Subtracting gives the elapsed minutes; adding 1440 when the result is negative handles the overnight case automatically. From the total minutes, integer division by 60 gives whole hours and the remainder gives minutes, while plain division by 60 gives the decimal-hours figure that multiplies directly by an hourly rate.
Worked example — a working day
Scenario: clock in at 09:30, clock out at 17:45.
The shift is 495 minutes — 8 hours 15 minutes, or 8.25 decimal hours, which at any wage multiplies straight through for pay. The overnight case works the same way: 22:00 to 06:00 looks negative (360 − 1320 = −960), so adding 1440 gives 480 minutes, exactly 8 hours. A plain day shift such as 09:00 to 17:00 needs no wraparound and comes to 480 minutes. Whichever form you need — h:m for a schedule, decimal for payroll — the calculator shows them side by side.
Frequently Asked Questions
Minutes since midnight, subtracted. 09:30→17:45 = 495 min = 8h 15m.
If end < start, add 24 h. 22:00→06:00 = 8h (480 min).
minutes ÷ 60. 495 min = 8.25 h. Used for payroll and billing.
÷ 60 for hours, remainder for minutes. 495 = 8 r15 → 8h 15m.
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