Time Duration Calculator
Calculate the duration between two times in hours and minutes, for same-day or overnight spans, with step-by-step math.
Time Duration Calculator — input your values
What does this everyday calculator do?
The time duration calculator finds how long a span lasts between two clock times, giving the result in hours and minutes as well as total minutes and decimal hours.
It supports both same-day spans and overnight shifts that cross midnight. The step-by-step breakdown shows the conversion of each time into minutes, the subtraction, and the conversion of the remainder back into hours and minutes.
Formula and variables
One day has 24 × 60 = 1,440 minutes, which is why an overnight span adds 1,440 to the end time.
| Symbol | Meaning |
|---|---|
| Hours | Hours in the span |
| Minutes | Minutes left over |
| Total minutes | Duration expressed entirely in minutes |
Worked example
A shift runs from 9:00 AM to 5:30 PM on the same day.
- Start: 9 h × 60 + 0 = 540 minutes.
- End: 17 h × 60 + 30 = 1,050 minutes.
- Duration: 1,050 − 540 = 510 minutes = 8 hours and 30 minutes.
Answer: The shift lasts 8 hours and 30 minutes.
Tips and common mistakes
Tips
- For overnight spans, remember the end time is on the next calendar day — the calculator adds a full 24 hours automatically.
- Decimal hours are useful for payroll: 8.5 hours means 8 hours and 30 minutes.
- To find elapsed time across both a day and a time, pair this calculator with the date calculator.
- When the start and end minute are the same, the minutes simply cancel, leaving a whole number of hours.
Common mistakes to avoid
- Forgetting that 60 minutes make one hour when adding or subtracting time.
- Treating an overnight end time as the same day, which shortens the span by 24 hours.
- Reading 8.5 as 8 hours and 5 minutes — the decimal means 8 hours and 30 minutes.
Time Duration Calculator — frequently asked questions
How do I calculate the duration between two times?
Convert both times to minutes past midnight, subtract, and convert the result back to hours and minutes. 9:00 AM to 5:00 PM is 540 to 1,020 minutes, a span of 480 minutes or 8 hours.
What does 'overnight' mean here?
It means the end time falls on the day after the start time. The calculator adds 24 hours to the end time, so 10 PM to 6 AM is 8 hours.
Why are minutes rounded to 5-minute steps?
The dropdowns offer 5-minute intervals for convenience, which covers most scheduling needs. Times in between can be approximated with the decimal-hours figure.
Can this calculate my work hours for the day?
Yes. Enter your clock-in and clock-out times, choose the matching time span, and read off the hours and minutes worked.
What is a good way to check the result?
Verify with the total minutes: multiply the hours by 60 and add the minutes. The result should equal the total minutes shown.
Does the calculator account for time zones or DST?
No. It works with wall-clock times on a single clock, so daylight saving shifts are not applied.