Time Duration Calculator

What Is the Time Duration Calculator?

This calculator finds the elapsed time between a start and end clock time -- how long a meeting, task, or shift lasted. It correctly handles overnight spans, where the end time is technically "earlier" than the start time because it falls after midnight.

How to Use This Calculator

Enter a start time and an end time (24-hour or your browser's local time picker format). The result shows the elapsed duration in hours and minutes, plus a decimal-hours figure for payroll or invoicing use.

How the Duration Is Calculated

Worked Example

Practical Uses

• Timing a meeting, class, or work session's length
• Checking an overnight shift's duration for payroll
• Estimating a task's time cost from its start and end times

For a full day's clock in/out punches (including a lunch break), see the Time Card Calculator. To round the result to the nearest quarter hour for payroll, use the Hours Calculator.

Step-by-Step: Getting a Reliable Duration

Enter the start time and the end time, then read the hours and minutes, the decimal-hours figure, and whether the span crosses midnight. Double-check AM and PM on both entries first, because a single wrong meridiem is the most common cause of a result that looks off by twelve hours. If you use a 24-hour picker, 17:30 is unambiguous and avoids that problem entirely.

More Worked Examples

A hypothetical 7:45 AM to 4:10 PM workday is 8 hours 25 minutes, or about 8.42 decimal hours (25 divided by 60 is 0.4167). An overnight case: 11:15 PM to 7:00 AM crosses midnight and comes to 7 hours 45 minutes, or 7.75 decimal hours. Converting the minutes portion by dividing by 60 is the step people most often get wrong by hand, for example writing 8.25 for 8 hours 25 minutes when the correct decimal is closer to 8.42.

An Edge Case Worth Knowing

If the start and end times are identical, the tool treats the span as zero minutes, not 24 hours. The tool only rolls over to the next day when the end time is earlier than the start time. So if you genuinely worked from 8:00 AM one morning to 8:00 AM the next, this calculator cannot express that as 24 hours. Use the Elapsed Time Calculator with full dates for anything of a day or longer.

Common Mistakes

• Forgetting to subtract unpaid breaks. The result is the full span between the two times. If a lunch break was unpaid, subtract it separately or use a tool designed for punch pairs.
• Using the decimal figure as if it were minutes. 8.5 hours means eight and a half hours, not 8 hours 50 minutes.
• Assuming daylight saving changes are handled. The tool works on clock times only, so a shift that spans a clock change may differ by an hour from the real elapsed time.
• Copying a rounded decimal into an invoice. Rounding rules differ between employers and clients, so use the exact figure unless you have been told which increment to use.

How to Interpret the Decimal Hours

Decimal hours are the number to multiply by a rate. At a hypothetical rate of 22 dollars per hour, 7.75 hours would be 170.50 dollars before any taxes or deductions. Whether time is rounded, paid in full minutes, or capped depends on your employer's policy and the labor rules where you work, so confirm those with your payroll department or the relevant labor agency instead of assuming this tool's exact figure is what appears on a paycheck.

Frequently Asked Questions