Subtracts a start clock time from an end clock time to return the elapsed duration in hours and minutes, with optional handling for shifts that cross midnight.
duration = endTime − startTime
The calculator converts each HH:MM clock time into total minutes from midnight, subtracts the start minutes from the end minutes, and converts the difference back into a clean hours-and-minutes breakdown. If the end time falls before the start time and the “crosses midnight” box is checked, 24 hours are added to the end time so the duration measures the overnight span correctly. Decimal hours, total minutes, and total seconds are all derived from the same subtraction so every output is internally consistent.
How many hours and minutes elapse between a 09:15 start time and a 17:45 end time on the same day?
This is the canonical worked example for an 8.5-hour workday with a 30-minute unpaid lunch already removed.
Clock arithmetic differs from regular arithmetic because the day wraps at midnight. The 24-hour notation makes the subtraction straightforward: a time like 17:45 is just 1065 minutes from midnight, and the elapsed duration between two times is the difference between their minute counts. When the end time is earlier than the start time, the calculator can treat the end time as the next day (adding 1440 minutes) so an overnight shift returns a positive duration. Decimal hours (510 min ÷ 60 = 8.5 h) are the standard format for payroll, billing, and timesheets.
Convert each clock time to total minutes from midnight, subtract the start from the end, then convert the difference back into hours and minutes. For 09:15 to 17:45 that is 1065 − 555 = 510 minutes, which is 8 hours and 30 minutes or 8.5 decimal hours.
Subtract the start time from the end time and convert the result to hours. If the end time is later in the same day, the duration is positive directly; if the end time is the next day, add 24 hours to the end before subtracting so the answer comes out positive.
Enter the clock-in time as the start and the clock-out time as the end. The calculator returns the elapsed duration in hours and minutes plus decimal hours, which is the standard format for payroll. Subtract any unpaid breaks manually before recording the total.
Check the “End time is the next day (crosses midnight)” box. The calculator then adds 24 hours to the end time before subtracting, so an overnight shift from 22:00 to 06:00 returns 8 hours rather than a negative value.
Divide the total elapsed minutes by 60. For example, 8 hours and 30 minutes equals 8 × 60 + 30 = 510 minutes, and 510 ÷ 60 = 8.5 decimal hours. The calculator shows the decimal-hour value alongside the HH:MM breakdown for billing and payroll.
duration = endTime − startTime, measured in minutes. If the end time falls before the start time on the same day and the duration is intended to span midnight, add 24 hours (1440 minutes) to the end time before subtracting.
Convert AM/PM times to 24-hour notation before entering them. For example, 9:15 AM stays as 09:15 and 5:45 PM becomes 17:45. The native browser time picker on most devices accepts either notation and stores the value as 24-hour HH:MM.
Yes — they refer to the same instant. The calculator accepts 24:00 as an end-of-day marker so that an input of 00:00 to 24:00 returns a full 1440-minute (24-hour) day. The next day's clock starts at 00:00.
Reference: Durations are reported in whole minutes. Seconds are derived by multiplying minutes by 60 and are exact whenever the inputs are HH:MM.
The calculator subtracts the start clock time from the end clock time after converting both to minutes-from-midnight:
Where:
For overnight spans where the end time falls before the start time on the clock, check the “crosses midnight” box. The calculator then adds 24 hours (1440 minutes) to the end time before subtracting so the answer remains positive.
Work Hours
A salaried employee clocks in at 09:15 and out at 17:45 on the same calendar day. Payroll needs the elapsed shift length in both HH:MM and decimal-hour form.
the shift is 8 hours and 30 minutes long, or 8.5 decimal hours for payroll.
This is the calculator's default example because it covers the most common scenario — a typical workday with no overnight wrap.
Overnight Shift
A night-shift worker clocks in at 22:00 and out at 06:00 the following day. The end time is earlier than the start time on the clock, so the calculator needs to know the span crosses midnight.
the overnight shift is exactly 8 hours.
Always check the "crosses midnight" box for overnight spans; otherwise the calculator returns an error because the raw subtraction is negative.
Billable Meeting
A consultant runs a meeting from 14:00 to 14:30 and needs to record the time in decimal hours for an invoice.
the consult is 0.5 decimal hours, the standard format for time tracking and invoicing software.