CALCULATE / TIMEDROP

Duration calculator

Add or subtract hours, minutes and seconds, including totals longer than a day.

First duration

Operation

Second duration

Use H:MM or H:MM:SS. Hours may exceed 24.

HOURS : MINUTES : SECONDS

4:15:00

15,300 total seconds · 4.25 decimal hours

HOW IT WORKS

Duration calculator, explained.

Enter a duration as H:MM or H:MM:SS.
Choose addition or subtraction and enter the other duration.
Copy the result as hours, decimal hours or total seconds.

Durations are elapsed amounts, not clock times. A result of 27:30:00 means 27 hours and 30 minutes rather than 3:30 on a particular date. Decimal hours divide total seconds by 3,600; decimal output is rounded to six places.

Can the result be negative?

Yes. Subtracting a longer duration from a shorter one produces a negative result.

Why is 1:30 equal to 1.5 hours?

Thirty minutes is half an hour. Decimal hours use fractions of an hour, not a two-digit minute field.

Every minute, sorted.

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