Time Duration Calculator
The exact time between two times or dates — free, no signup
Time duration calculator — hours between two times
Enter any two times — or two full dates — and get the exact elapsed time between them: 9:00 to 17:30 is 8 hours 30 minutes, shown as h:m:s, as total minutes (510), and as decimal hours (8.5) for timesheets and payroll.
Common uses: work shifts and adding up a week of work hours, workout and study session lengths, travel legs, and how long you slept. For minutes-to-decimal conversions, see the decimal hours table.
How many hours is a shift?
Common start and end times, worked out:
- 9 AM to 5 PM is 8 hours.
- 9 AM to 5:30 PM is 8 hours 30 minutes (8.5 hours).
- 8 AM to 4:30 PM is 8 hours 30 minutes (8.5 hours).
- 8 AM to 5 PM is 9 hours.
- 7 AM to 3:30 PM is 8 hours 30 minutes (8.5 hours).
- 10 AM to 7 PM is 9 hours.
- 12 PM to 8 PM is 8 hours.
- 6 AM to 2:30 PM is 8 hours 30 minutes (8.5 hours).
- 10 PM to 6 AM is 8 hours, overnight.
- 7 PM to 7 AM is 12 hours, overnight.
Frequently asked questions
How do I calculate the hours between two times?
Enter a start and end time and press Calculate Duration. The result shows hours and minutes, the total in minutes, and decimal hours for payroll.
Does it work across midnight?
Yes. When the end time is earlier than the start time, the calculator treats it as the next day: 10:00 PM to 6:00 AM is 8 hours, not negative time.
Can it calculate the duration between two dates?
Yes — both ends take a date as well as a time. The result breaks the span down calendar-accurately into years, months, days, hours and minutes, and Show details gives it as a total number of days, weeks or hours.
What are decimal hours?
Decimal hours express minutes as a fraction of an hour (minutes ÷ 60), which is what payroll math needs: 8 hours 30 minutes is 8.5 hours. The result shows both formats.
Can I add up several time periods?
Yes. Every calculation is kept in the Recent Calculations list — select any of them and press Sum Selected to total multiple durations, for example separate work sessions in a day.
All ClockMath tools
- Work hours calculator — total shifts with breaks, decimal hours, and gross pay
- Overtime calculator — regular vs overtime hours, and what time and a half pays
- Timezone converter — any two places, with automatic daylight-saving handling
- Stock market hours — live open/closed status for major exchanges in your timezone
- Decimal hours converter — minutes to decimal (and back) with the full payroll chart
- Sleep calculator — hours slept and sleep-cycle bedtimes for any wake-up time
- Countdown timer — count down to any date and share it
- Daily time quiz — five clock-math questions a day, with a leaderboard
- Guides — practical articles on work hours, payroll time math, and timezones