Time duration

Calculate a clock-time duration

Use this calculator for a work session, a journey, an appointment, or another interval shorter than twenty-four hours. Enter the start and finish clock readings to see hours, remaining minutes, and total minutes. The form has no date or time-zone fields, so it measures clock-time differences rather than the elapsed time between two dated instants.

1. Enter the start time

   Choose the hour and minute when the interval begins. Check AM and PM if your device presents a twelve-hour time field.

2. Enter the finish time

   If the finish is earlier on the clock than the start, the calculator treats it as a finish on the next day.

3. Read the duration

   Select Calculate. The result gives whole hours and remaining minutes, with the total number of minutes underneath.

Same-day and overnight examples

In the overnight example, there are twenty minutes from 23:40 to midnight and fifteen minutes from midnight to 00:15. Together they make thirty-five minutes. Equal clock readings are treated as zero, because the inputs do not indicate whether a whole day has passed.

Hours and minutes are not decimal hours

Three hours and thirty minutes is 3.5 decimal hours, not 3.30 hours. To convert a result for a timesheet, divide the total minutes by sixty. A forty-five-minute interval becomes 0.75 hours; an interval of one hour and fifteen minutes becomes 1.25 hours. Check whether a timesheet expects decimal hours or an hours-and-minutes format before copying the result.

Handling breaks and several sessions

This form calculates one continuous interval. It does not automatically subtract lunch or other breaks. For a day split into several working sessions, calculate each session separately and add the total minutes. Alternatively, calculate the full interval and subtract the recorded break minutes. Keep the break calculation visible so another person can understand how the final total was obtained.

The limits of a clock-only calculation

An interval from 09:00 to 10:00 could mean one hour, twenty-five hours, or a longer period if dates are omitted. This tool uses the first interpretation. Daylight saving can also make a clock-time difference differ from real elapsed time. To measure a dated interval crossing such a change, you need both dates and their time-zone offsets.

For a session happening now, use the stopwatch. For a distance between calendar dates, use date difference. The elapsed time guide explains how to choose the right approach when clock readings and actual elapsed time differ.