Time Duration Calculator

Frequently asked questions

How does it handle times that cross midnight?

When the end time is earlier than the start time, the calculator assumes the end is on the next day and adds 24 hours. So a shift from 22:00 to 06:00 is counted as 8 hours, which is what you want for overnight work or sleep tracking.

How do I calculate billable hours for a timesheet?

Enter your start time and end time in the duration-between mode. The result shows hours and minutes, plus a decimal-hours figure that is useful for billing. For example, a session from 09:15 to 12:45 is 3 hours 30 minutes, or 3.5 decimal hours. Multiply the decimal value by your hourly rate to get the billable amount.

What is the difference between decimal hours and clock format?

Clock format expresses time as hours and minutes, such as 2h 30m. Decimal hours expresses the same duration as a single number, such as 2.5. Decimal format is easier to multiply by a rate or add to a spreadsheet. Thirty minutes is always 0.5 in decimal format, fifteen minutes is 0.25, and forty-five minutes is 0.75.

Can I add more than 24 hours to a time?

Yes. When you add a duration that pushes the result past midnight, the calculator shows the resulting clock time and notes how many days forward the result falls. For example, adding 30 hours to 08:00 gives 14:00 the following day, displayed as 14:00 (+1 day). This is useful for planning shift handovers or multi-day transit times.