Time Calculator
Add and subtract time durations in hours, minutes, and seconds with automatic unit overflow and decimal hour conversions.
About the Time Calculator
The Time Calculator enables fast addition and subtraction of time intervals expressed in hours, minutes, and seconds. Because time uses base-60 (sexagesimal) arithmetic rather than base-10, adding hours and minutes manually frequently leads to regrouping errors.
This tool automatically handles 60-second and 60-minute rollovers, making it ideal for video editors calculating footage runtime, project managers tracking billable tasks, pilots logging flight durations, and athletes analyzing workout splits.
How to Calculate Time
Enter hours, minutes, and seconds for Time 1.
Choose the operation: Add (+) or Subtract (-).
Enter hours, minutes, and seconds for Time 2.
Click Calculate to see the consolidated hours, minutes, seconds, and total decimal hours.
Sexagesimal Time Summation Formula
Total Seconds = (H1 × 3600 + M1 × 60 + S1) ± (H2 × 3600 + M2 × 60 + S2) Hours = ⌊Total Seconds / 3600⌋ Minutes = ⌊(Total Seconds mod 3600) / 60⌋ Seconds = Total Seconds mod 60
All input time blocks are converted to total seconds, added or subtracted, and then converted back into normalized hours, minutes, and seconds.
Variable Descriptions
- H1, M1, S1
- Hours, minutes, and seconds of the first duration
- H2, M2, S2
- Hours, minutes, and seconds of the second duration
Worked Example
Important Considerations & Tips
- There are 60 seconds in a minute and 60 minutes in an hour.
- To convert minutes to decimal hours, divide the minutes by 60 (e.g., 30 minutes = 0.5 hours).
- If subtracting a larger time from a smaller time, the result is displayed as a negative time offset.
Frequently Asked Questions
How do you convert minutes into decimal hours?
Divide the number of minutes by 60. For example, 45 minutes divided by 60 is 0.75 hours. Therefore, 2 hours and 45 minutes equals 2.75 decimal hours.
What happens when seconds exceed 60?
Every block of 60 seconds automatically converts into 1 minute and carries over into the minutes column.
Can this tool calculate flight or video editing timecodes?
Yes. It precisely sums multiple takes, clips, or flight legs in hours, minutes, and seconds.
Related Calculators
Hours Calculator
Free online hours calculator. Calculate total work hours, lunch breaks, decimal hours, and gross pay between start and end times for timesheets.
Date Calculator
Free online date calculator. Calculate the exact number of days, weeks, and business days between two dates, or add/subtract days from any date.
Pace Calculator
Free online running pace calculator. Calculate pace per kilometer (min/km), pace per mile (min/mi), and speed (km/h, mph) for 5K, 10K, half marathon, and marathon races.
Age Calculator
Free online age calculator. Find your exact age in years, months, weeks, days, and hours from your birth date to today or any target date.