Time Duration Calculator
Calculate time duration between two times or dates
Duration
8.50 hours
Total Minutes
30600 seconds
How it works
A time duration calculator finds the elapsed time between a start and end time. It subtracts the start from the end, carrying across the 60-minute and 24-hour boundaries — including spans that cross midnight.
Duration
Duration = end time − start time (add 24 h if it crosses midnight)
- start / end
- the two clock times
Worked example
- Start 9:15 AM
- End 5:45 PM
- 5:45 PM = 17:45
- 17:45 − 9:15
8 hours 30 minutes.
Good to know
- When the end time is earlier than the start, it crossed midnight — add 24 hours.
- Subtract unpaid breaks to get worked time from a shift duration.
- Convert to decimal hours (8.5) for payroll math.
Related Calculators
Frequently Asked Questions
How do I calculate the time between two times?
Subtract the start from the end, borrowing 60 minutes when needed since time is base-60. From 9:45 AM to 2:20 PM is 4 hours 35 minutes — the calculator handles the borrowing automatically.
How do I handle a duration that crosses midnight?
Add 24 hours to the end time before subtracting. A shift from 10:30 PM to 6:15 AM is (6:15 + 24:00) - 22:30 = 7 hours 45 minutes.
How do I convert minutes into decimal hours?
Divide minutes by 60: 15 minutes = 0.25, 45 minutes = 0.75. So 7 hours 45 minutes is 7.75 hours — the format payroll systems and billing software expect.
How do I add multiple durations together?
Add the minutes first, carry each full 60 into the hours, then add hours. For example 2:50 + 1:25 = 3 hours 75 minutes = 4 hours 15 minutes.
Does daylight saving time affect duration calculations?
Yes — on transition nights a wall-clock interval can be an hour shorter or longer than it appears. For payroll or travel spanning the spring-forward or fall-back night, adjust by the skipped or repeated hour.