Calculate the duration between two clock times, adjust a clock time, or add and subtract multiple durations. Total durations can exceed 24 hours.
The calculator works in whole seconds and keeps the day offset separate from the displayed 24-hour clock time, so a result that crosses midnight is never hidden.
Enter two 24-hour clock times to get the elapsed hours, minutes, and seconds. When an end time is earlier than the start, the overnight option treats it as a time on the following day.
Add or subtract any non-negative number of hours, minutes, and seconds. The displayed clock result wraps to a 24-hour day while a separate day offset preserves the complete answer.
Add a row for each duration and choose + or −. For example, 1:30 + 2:45 + 0:50 = 5:05:00. Totals can exceed 24 hours or be negative. Blank rows are ignored.
Leave Treat an earlier end time as the next day selected when the range crosses midnight. Clear it only when you intentionally want the same-day subtraction shown as a negative duration.
Time duration finds the difference between two clock times. Add or subtract adjusts one clock time. Add multiple durations totals a list of durations without a start time.
The clock result wraps within 24 hours, while Day rollover reports how many days forward or backward the full calculation moved. This keeps additions such as 30 hours from looking like a simple 6-hour result.
No. The tool calculates clock times and durations; it does not apply calendar dates, time zones, daylight saving changes, work schedules, or automatic break deductions.
Choose Add multiple durations. Enter each duration as hours:minutes or hours:minutes:seconds and choose + or − for each row. The result is a total duration, not a clock time: 23:00 + 2:00 gives 25:00:00, not 01:00:00.
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