Time Calculator

Whether you need to add up work hours, find an end time from a start time and duration, or subtract time periods, this time calculator handles any time arithmetic quickly and accurately.

How to Use This Calculator

1. Add/subtract times: Enter multiple time values (HH:MM:SS format) with + or − operations.
2. Find end time: Enter start time + duration → get end time.
3. Find duration: Enter start time and end time → get total duration.
4. Click Calculate for instant results that correctly handle midnight crossings and AM/PM.

Example Calculations

Add times: 1:45:30 + 2:30:45 = 4:16:15

Start: 9:00 AM, Duration: 7h 45min → End: 4:45 PM

Start: 10:30 PM, End: 2:15 AM → Duration: 3 hours 45 minutes

Time Format Tips

• Enter time as HH:MM or HH:MM:SS (hours:minutes:seconds)
• For durations over 24 hours, the calculator shows total hours (e.g., 26:30:00 for 26 hours 30 minutes)
• Midnight (12:00 AM = 00:00 in 24-hour time) is handled automatically

Common Uses

• Calculating work shift hours
• Planning daily schedules
• Adding up time logs for billing
• Countdown timers and project duration estimates

Frequently Asked Questions

How do I calculate total hours worked in a week?

Enter each day's work duration and add them together. For example: Mon 8:30 + Tue 7:45 + Wed 8:00 + Thu 7:30 + Fri 8:15 = 40 hours. Use our Hours Calculator for this specifically.

How does the time calculator handle overnight periods?

The calculator detects when end time is before start time and assumes the period crosses midnight. A shift from 10 PM to 6 AM = 8 hours, not −16 hours.

Conclusion

Time arithmetic can be confusing with hours and minutes not working in base-10. This calculator takes the math off your hands — any time addition, subtraction, or duration calculation, solved instantly.

Related: Hours Calculator | Time Card Calculator | Date Calculator