Use this free time duration calculator to find the time between two times in seconds. Enter a start time and an end time, and the time duration calculator shows the duration in hours and minutes, in total minutes, and in decimal hours instantly. There is no sign-up, no account, and no personal information needed, and your times are calculated in your browser and are not sent to us. It works for work shifts, study sessions, travel, and events in the United States, the United Kingdom, and Canada, in 12-hour or 24-hour time.
Contents: Formula · How to use · Examples · Tips · FAQ · Related tools
No sign-up required. This time duration calculator works in your browser, so the times you enter are not stored or sent to us.
How to Find Time Duration: Time Duration Calculator Formula
Duration is the difference between two times on the same clock. Convert each time to minutes since midnight, subtract the start from the end, and then convert the result back into hours and minutes. If the end time is on the next day, add 24 hours, or 1,440 minutes, to the end time first. This time duration calculator uses exactly that method.
Duration in minutes = End time in minutes − Start time in minutes, plus 1,440 if overnight
For example, 09:30 to 17:45 gives 1,065 − 570 = 495 minutes, which is 8 hours and 15 minutes, or 8.25 hours. For an overnight shift from 22:00 to 06:00, add 1,440 minutes to 06:00, giving 1,800 − 1,320 = 480 minutes, which is 8 hours exactly. The time duration calculator shows all three forms — hours and minutes, total minutes, and decimal hours — so you can use the form your timesheet or plan needs.
How to Use the Time Duration Calculator
Choose the start time in the first box and the end time in the second box. If the end time is after midnight, choose Yes — overnight in the third box, so the time duration calculator does not treat the end time as earlier on the same day. Tap Calculate Duration to see the duration in hours and minutes, total minutes, and decimal hours. If you need to subtract a break, calculate the full duration first, then subtract the break separately, or calculate the two parts before and after the break and add them.
Remember that times are entered in the same time zone, and this time duration calculator does not adjust for daylight saving changes or time-zone travel. For a shift that crosses a clock change, check the actual elapsed time on that date. The result is exact for ordinary same-day and overnight periods on a 24-hour clock.
Time Duration Calculator Examples
Example 1 — 09:30 to 17:45. Duration = 1,065 − 570 = 495 minutes = 8 hours 15 minutes = 8.25 hours.
Example 2 — 08:00 to 12:30. Duration = 750 − 480 = 270 minutes = 4 hours 30 minutes = 4.50 hours.
Example 3 — 22:00 to 06:00, overnight. Duration = (360 + 1,440) − 1,320 = 480 minutes = 8 hours 0 minutes = 8.00 hours.
These time duration calculator examples show why converting to minutes first helps: it avoids mistakes when the minutes in the end time are smaller than the minutes in the start time, for example from 09:45 to 11:15, which is 90 minutes, not 70 minutes.
Time Duration Calculator Tips
Use decimal hours for pay and billing, because 8.25 hours is easier to multiply by an hourly rate than 8 hours 15 minutes. Use hours and minutes for schedules and rosters, because people read them more easily. Always check the overnight setting for night work, and double-check AM and PM if you use 12-hour time. For general background on time measurement, see the Wikipedia guide to time. If you want to convert pay from hourly to yearly, use the hourly to salary calculator, and to count down to an event, use the countdown timer.
Time Duration Calculator FAQ
What does a time duration calculator do? A time duration calculator finds the elapsed time between a start time and an end time, and shows it in hours and minutes, total minutes, and decimal hours.
How do I calculate duration by hand? Convert both times to minutes since midnight, subtract the start from the end, and convert back: divide by 60 for hours, and keep the remainder as minutes. Add 1,440 minutes to the end time if it is on the next day.
Can it handle overnight periods? Yes. Choose Yes — overnight, and the time duration calculator adds 24 hours to the end time, so 22:00 to 06:00 gives 8 hours, not a negative result.
Does it handle dates as well as times? This tool measures time within a day and overnight. For a period over several days, calculate the full days separately and add the time duration for the remaining part.
What is the difference between 8.25 hours and 8 hours 15 minutes? They are the same duration. Decimal hours divide minutes by 60, so 15 minutes is 0.25 hours, and 30 minutes is 0.50 hours.
How do I subtract a break from a shift? Calculate the full duration first, then subtract the break separately — or calculate the two parts before and after the break and add them.
Related Tools
Try the Hourly to Salary Calculator to turn hours into pay, the Salary to Hourly Calculator for the reverse rate, the Countdown Timer to count down to a date and time, and the Average Calculator to average a set of numbers. Return to the PDGPT homepage to browse all free calculators by category.