Everyday Calculation

Enter time as hh:mm:ss e.g., 12:45

Start time: AMPM

End time: AMPM

Time format: 12-hour 24-hour

To calculate hours worked or sum up a group of time intervals, use our timesheet calculator.

Download: Use this time calculator offline with our all-in-one calculator app for Android and iOS.

Time interval formula

To calculate time difference, we convert both time values to seconds since midnight using the following formula:
time_m = hh*3600 + mm*60 + ss

if (start_timem < end_timem)
T = end_timem - start_timem
else
T = 86400 - start_timem + end_timem
where,
time_m - Time in seconds since midnight
T - Time interval in seconds

Now convert the time interval to hours, minutes and seconds to arrive at the final result.
h = ⌊T/3600⌋, min = ⌊T/60⌋ mod 60, sec = T mod 60

The steps listed above are for 24-hour time format.

Sample calculation: Find time duration between 09:00AM and 05:00PM.

Ans. The time duration is 8 hour(s), 0 minute(s), and 0 second(s).
Time difference in hours: 8
Time difference in minutes: 480
Time difference in seconds: 28800

More Date & Time Calculators

• Time Addition/ subtraction
• Clock time calculator
• Date Duration
• Hours Minutes Converter
• Working days
• Unix timestamp
• World Time