A time duration calculator finds the elapsed time between a starting time
and an ending time. It can display the result as hours, minutes and seconds,
HH:MM:SS, total minutes or decimal hours.
Use âBetween timesâ for same-day or overnight periods, âBetween dates & timesâ for longer spans, or âMultiple time blocksâ to total separate sessions.
How to Calculate Time Duration
Convert both times to the same clock format, convert them to total seconds or minutes, and subtract the start from the end. If the period crosses midnight, add 24 hours to the end value before subtracting. Deduct any break to find net duration.
- Convert AM/PM times to 24-hour format when necessary.
- Convert each time to seconds:
hours Ă 3,600 + minutes Ă 60 + seconds. - Add 86,400 seconds if the end is on the next day.
- Subtract the start value from the adjusted end.
- Subtract an optional break and convert the result.
Gross duration = End time â Start time
Net duration = Gross duration â Break
Decimal hours = Hours + (Minutes Ă· 60) + (Seconds Ă· 3,600)
Worked Examples
Same-Day Time Difference
How long is 9:15 AM to 5:45 PM?
- 9:15 AM = 555 minutes after midnight.
- 5:45 PM = 17:45 = 1,065 minutes.
- 1,065 â 555 = 510 minutes.
- 510 minutes = 8 hours 30 minutes = 8.50 hours.
Answer: 8 hours 30 minutes.
Overnight Duration With a Break
How long is 10:00 PM to 6:30 AM with a 30-minute break?
- Select next day for the end.
- Gross duration = 8 hours 30 minutes.
- Deduct 30 minutes.
Answer: 8 net hours.
Time Duration Output Formats
Hours and minutes are easiest to read, while decimal hours are convenient for billing and spreadsheets.
| Duration | HH:MM | Decimal | Minutes |
|---|---|---|---|
| 15 minutes | 00:15 | 0.25 | 15 |
| 30 minutes | 00:30 | 0.50 | 30 |
| 45 minutes | 00:45 | 0.75 | 45 |
| 1h 20m | 01:20 | 1.33 | 80 |
| 7h 45m | 07:45 | 7.75 | 465 |
Common Time Calculation Mistakes
- Wrong day: an earlier end time needs âNext dayâ when the period crosses midnight.
- Noon and midnight: 12:00 PM is noon; 12:00 AM is midnight.
- Minutes as hundredths: 30 minutes is 0.50 hours, not 0.30.
- Forgotten breaks: gross elapsed time and net work time may differ.
- Mixed time zones: convert both values to the same zone first.
- Equal times: same-day means zero; next-day means 24 hours.
How to Verify the Answer
Convert the answer back to minutes or seconds and add it to the start. For example, adding 510 minutes to 9:15 AM gives 5:45 PM. If a break was deducted, add it back before comparing with the original end.
Limitation: values are treated as local clock times. This tool does not convert time zones. Daylight-saving changes can affect real elapsed time, so use a common reference such as UTC when zone-aware precision is required.
For calendar-only spans, use the Date Difference Calculator.
Frequently Asked Questions
Convert both times to total minutes or seconds and subtract the start from the end. Add 24 hours first if the end is on the next day.
Select âNext dayâ for the end time. For example, 11:00 PM to 2:00 AM is 3 hours.
Same-day means zero duration. Select next day if the second occurrence is 24 hours later.
Enter the total break in minutes. The calculator subtracts it from gross duration to show net duration.
Divide minutes by 60 and add them to whole hours. Seven hours 45 minutes equals 7.75 hours.
Yes. Choose Between dates & times for an interval longer than 24 hours.
No. Convert both timestamps to the same time zone before entering them.
It can. For zone-aware elapsed time, convert both timestamps to UTC first.
Calculation methodology
Utilixea converts values to total seconds, applies the selected next-day or date offset,
subtracts the start, and deducts any optional break. The result is converted into readable
duration, HH:MM:SS, decimal hours and total minutes.
Prepared by: Utilixea Editorial Team | Logic reviewed: July 19, 2026
Related Time Calculators
Try the Date Difference Calculator, Countdown Calculator, Age Calculator, or Hours to Minutes Converter.
