Time Duration Calculator

What Is a Time Duration Calculator?

A time duration calculator finds how much time passes between two clock times, or between two full dates and times. Use it for shift hours, timesheets, travel and flight durations, study sessions, cooking and baking, and any situation where you have a start and an end and need the length. The result is shown as hours, minutes and seconds, and across dates it includes days.

How to Find the Time Between Two Times

1. Write down both times. Identify the start and the end.
2. Convert to 24-hour time if needed. AM hours stay the same; for PM hours add 12, so 1:00 PM is 13:00. (12:00 AM is 00:00, and 12:00 PM is 12:00.)
3. Subtract the start from the end. If the end minutes are smaller than the start minutes, borrow an hour — add 60 minutes to the end and reduce the end hour by one.

For example, from 9:45 AM to 2:20 PM: 14:20 − 9:45. The minutes (20) are smaller than 45, so borrow: 13:80 − 9:45 = 4 hours 35 minutes.

Worked Example

From 9:00 AM to 5:30 PM is 8 hours 30 minutes.

Times That Cross Midnight

When the end is earlier on the clock than the start — a night shift from 22:00 to 06:00, say — the event passes midnight. Add 24 hours to the end time before subtracting: (06:00 + 24:00) − 22:00 = 8 hours. If the two times fall on different dates, include the dates and the calculator accounts for the whole days in between.

Practical Uses

• Payroll: work out hours worked, remembering to deduct unpaid breaks.
• Travel: total journey time including connections; note that time zone changes shift the clock, not the elapsed time.
• Scheduling: check how long a meeting, a project phase or a recording ran.

Related Tools

To add or subtract time from a clock reading, use the Time Calculator. For calendar spans in days, months and years, use the Date Calculator, and for pay by the hour, convert wages with the Salary Calculator.