Time Duration Calculator
Hours between two times or dates, minus breaks, totalled across as many rows as you need.
Sessions
Times like 9:00 AM, 17:30, 2140 or 24:00 (end of day). Breaks in minutes (30) or as 0:45. An end time earlier than the start counts as the next day.
About the Time Duration Calculator
Enter when something started and ended, subtract any unpaid break, and get the duration as hours, minutes and seconds, as decimal hours and as total minutes. Use Clock times for shifts within a day or overnight — an end time earlier than the start is counted on the next day — and Dates and times for anything that runs over several days.
Add a row for every session to build a simple timesheet: each row shows its own result and the total updates as you type. Copy the result as text or download it as CSV for a spreadsheet. In date mode the calculator also notices when a session crosses a daylight-saving change in your time zone and can count the real elapsed time.
How to use it
- Choose Clock times or Dates and times.
- In each row, type the Start and End —
9:00 AM,17:30,2140and24:00all work — and, in date mode, pick the dates. - Type any unpaid Break in minutes (
30) or as hours and minutes (0:45). Give the row a Label such as Mon if you like. - Press Add row for the next session. The total at the bottom shows h:mm:ss, decimal hours and minutes; Copy or CSV exports every row and the total.
Examples
9:00 AM – 5:30 PM, break 30 min
8:00:00 = 8 hours = 480 minutes
22:00 – 06:30, break 45 min
7:45:00 = 7.75 hours (ends the next day)
Monday to Friday, 9:00 AM – 5:30 PM with 30-minute breaks
40:00:00 = 40 hours
Fri 2 Oct 2026 18:00 – Mon 5 Oct 2026 09:15
63:15:00 = 63.25 hours
Sat 24 Oct 2026 22:00 – Sun 25 Oct 2026 06:00 in London
8 hours on the clock face, 9 hours of real time
UK clocks go back from 02:00 BST to 01:00 GMT that night, so the hour from 01:00 to 02:00 happens twice.
Common uses
- Filling in a timesheet or checking hours worked before payroll.
- Totalling freelance or consulting sessions for an invoice in decimal hours.
- Working out how long a journey, event, fast or machine run lasted across midnight or several days.
Overnight shifts and midnight
In Clock times mode the calculator assumes that a session lasts less than 24 hours. If the end time is earlier than the start time — 22:00 to 06:30 — the end is taken to be on the next day and the row is marked “overnight”. A start and end at the same time gives 0 hours; for a 24-hour shift, switch to Dates and times and pick both dates.
Midnight can be written 00:00 or 12:00 AM at the start of a day, and 24:00 at the end of a day, so 22:00 to 24:00 is 2 hours.
Decimal hours and minutes
Payroll and billing systems often want hours as a decimal number: divide the minutes by 60, so 7 h 45 min is 7.75 hours and 7 h 20 min is 7.33 hours (rounded; marked with ≈). The total is shown both ways, together with the total in minutes (465 for 7 h 45 min) and the ISO 8601 duration (PT7H45M) used by many data formats.
Daylight saving time
Clock-face arithmetic does not know about daylight-saving changes. In Dates and times mode the calculator also asks your browser for the real elapsed time in your device’s time zone. When a session crosses a change, the row says so and you can choose to count the real time: a night shift in London from 22:00 on 24 October 2026 to 06:00 the next morning lasts 9 hours because clocks go back an hour; in late March a similar shift lasts 7 hours. India does not use daylight saving time, so Indian times never change this way.
Limitations
- Daylight-saving changes are checked for your device’s time zone only. For work done in another time zone, convert the times first with the time zone converter.
- No rounding rules (for example to the nearest quarter hour) and no pay or overtime calculations are applied — the durations are exact to the second.
- In clock-times mode a single row cannot be longer than 24 hours; use date mode for longer spans.
Privacy
Everything is calculated in your browser and nothing you type is uploaded. So that a timesheet survives a page reload, the rows and the chosen mode are saved in this browser’s local storage; press Reset to replace them with the example.
Frequently asked questions
How do I calculate the hours worked between two times?
Subtract the start time from the end time, then subtract unpaid breaks. Typing 9:00 AM, 5:30 PM and a break of 30 gives 8 hours. For a shift past midnight, such as 22:00 to 06:30, the calculator adds a day automatically.
How do I convert hours and minutes to decimal hours?
Divide the minutes by 60 and add them to the hours: 8 h 15 min = 8.25 hours, 8 h 40 min ≈ 8.67 hours. Every row and the total show decimal hours next to h:mm:ss.
How do I enter a break?
Type the unpaid break in minutes (30, 45) or as hours and minutes (1:15, 1h 15m). It is subtracted from that row only. Leave it empty if there was no break.
Can I total a whole week?
Yes. Add one row per day or session — up to 100 — and the total updates as you type. Use Copy to paste the list into an email, or CSV to open it in Excel or Google Sheets.
Does it handle daylight saving time?
In Dates and times mode, yes: if a session crosses a daylight-saving change in your device’s time zone, the row shows the difference and you can count the real elapsed time. Clock-times mode has no dates, so it always uses clock-face time.