Calculate hours and minutes between clock times, including overnight periods, or add and subtract fixed durations from a time of day.
Clock values are parsed as minutes after midnight. Same-day duration subtracts start from end; an earlier end is treated as the following day. No dates or timestamps are involved.
duration = end minutes − start minutes; if overnight, add 1,440 minutesSeven hours 30 minutes is 7.5 hours, not 7.30.
decimal hours = total minutes ÷ 60The quotient becomes the signed day offset and the remainder becomes the result time.
result = normalize(start minutes ± duration, 1,440)09:00 to 17:30 is 8 hours 30 minutes, 8.5 decimal hours, or 510 minutes.
22:00 to 06:00 is an overnight duration of 8 hours.
22:30 plus 3 hours is 01:30 on the next day; 02:00 minus 3 hours is 23:00 on the previous day.
Equal start and end times mean zero by default. Enable End next day to calculate exactly 24 hours.
00:00 is midnight. In 12-hour display, 12:00 AM is midnight and 12:00 PM is noon.
This tool does not account for dates, daylight-saving transitions, time zones, or leap seconds.
When end is earlier than start, the calculator automatically adds 24 hours and clearly reports the next-day assumption.
Hours may exceed 24, while minutes must be 0–59. The result preserves every whole day crossed as a signed day offset.
Native time inputs remain unambiguous 24-hour clock values internally. The result can be displayed as either 24-hour or 12-hour time.
Convert each clock time to minutes after midnight and subtract. If the end is earlier, add one day.
An earlier end time is automatically treated as the next day.
No. Thirty minutes is half an hour, so the decimal value is 7.5.
The clock result wraps within 24 hours and a signed day offset reports how many days were crossed.
It means midnight at the start of a day.
Yes in add/subtract modes. Hours are unrestricted within the supported validation range.
No. It performs pure clock arithmetic without a date or timezone.