Calculator

Time Duration Calculator

Calculate elapsed time between two times on the same day.

Choose both times.

How it works

If the end time is earlier than the start time, the calculator treats the end as occurring on the following day.

How elapsed time is calculated

Time duration is the difference between a starting time and an ending time. The calculation is easiest when both times use the same clock convention and are interpreted within the intended day or schedule.

Worked example

From 09:20 to 13:50, the elapsed duration is 4 hours and 30 minutes. For an interval that crosses midnight, the intended dates matter: 23:30 to 01:00 on the following day is 1 hour and 30 minutes.

Common mistakes

A clock time by itself does not always identify a unique interval. Be explicit about AM and PM, the date when midnight is crossed, and any daylight-saving transition that affects a real-world schedule.

When this tool is useful

Use it for study sessions, work blocks, meetings, travel planning, and simple time tracking. For dates separated by multiple calendar days, use the Date Difference Calculator instead.

Frequently asked questions

What is a time duration?

A time duration is the elapsed amount of time between two clock times or a total made by combining hours and minutes.

How should I handle a duration that crosses midnight?

A calculation that crosses midnight needs to treat the second time as occurring on the following day. The tool is intended to make that elapsed-time calculation easier.

Can I use decimal hours instead of hours and minutes?

This calculator is designed for conventional hours-and-minutes input. If you have decimal hours, convert the decimal portion to minutes before entering it.

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