09:00 to 17:30, with a 30-minute break
8 h 30 min − 30 min = 8 h
The elapsed time is 510 minutes. Subtracting the break leaves 480 minutes, or 8.00 hours.
Choose Same day for this interval.
Time and planning
Time Duration Calculator
Find the time between a start and end, with an optional break to subtract.
Calculate a time interval
Net duration after break
Enter your times, then select Calculate.
- Total elapsed time
- Break subtracted
- Net decimal hours
Your times and break are calculated in your browser and are not sent to a server.
Examples you can check
22:30 to 06:00, with a 30-minute break
7 h 30 min − 30 min = 7 h
The elapsed time is 450 minutes. Subtracting the break leaves 420 minutes, or 7.00 hours.
Choose Next day so the end falls after midnight.
10:00 to 11:20, with no break
80 min ÷ 60 ≈ 1.33 hours
The exact duration is 1 h 20 min. Its decimal-hour equivalent is approximately 1.33.
Twenty minutes is one third of an hour, not 0.20 hours.
How the calculation works
Each clock time is converted to minutes after midnight: hours × 60 + minutes. The elapsed interval is the end time minus the start time. Selecting Next day adds 1,440 minutes to the end time before subtracting.
The calculator subtracts your break from the elapsed interval. The remaining whole minutes are split into hours and minutes, then divided by 60 to produce decimal hours.
Hours and minutes are exact within the entered minute precision. Decimal hours are shown to 2 decimal places, rounded to the nearest value with exact ties away from zero. An ≈ marks a rounded decimal result; rounding never changes the underlying minute count.
Common questions
Why is my end time earlier than my start time?
If the interval continues past midnight, choose Next day. The calculator does not make this choice automatically, so a mistyped end time is not silently treated as an overnight interval.
Can I calculate more than 24 hours?
Yes. Next day means the following calendar day, even when the end clock time is later than the start clock time. For example, 09:00 to 17:30 on the next day is 32 hours 30 minutes. The maximum supported span is 47 hours 59 minutes: 00:00 to 23:59 on the next day. Longer spans need a calculator that accepts dates.
Does this account for daylight saving or time zones?
No. This is a wall-clock calculation using a 24-hour day. It does not accept actual dates, time zones, or daylight-saving changes. An actual interval across a clock change can differ from the result shown here.
Can the break equal the whole interval?
Yes. A break equal to the elapsed time produces a net duration of zero. A longer break is rejected. Use whole, nonnegative minutes; a blank break field is treated as zero.
Is 8 hours 30 minutes the same as 8.30 hours?
No. Convert the minutes by dividing by 60. Thirty minutes is 0.50 hours, so 8 hours 30 minutes is 8.50 decimal hours. The calculator shows both formats to make the difference clear.