Time Duration Calculator

What the Time Duration Calculator does

This is a simple clock-time tool: type a start time and an end time, and it tells you exactly how much time sits between them, in hours and minutes plus a total-minutes figure. It is handy for working out shift length, billable hours, how long a meeting ran, sleep duration, or the gap between two events. It even handles overnight spans, so if you start at 22:00 and end at 06:00 it correctly returns 8 hours instead of a negative number.

How to use it

1. In the Start time (HH:MM) field, type your starting clock time, for example 09:00.
2. In the End time (HH:MM) field, type the ending time, for example 17:30. Use 24-hour format.
3. Press Calculate.
4. Read the result: a big Duration line (like 8 h 30 min) and a Total minutes value below it.
5. Change either field and calculate again to compare scenarios.

Tip: if the end time is earlier than the start time, the calculator assumes you crossed midnight and adds a full day automatically.

Why use this one

It runs entirely in your browser, so nothing you type is sent anywhere and there is nothing to install. It is free, needs no account, and returns the answer the instant you click. Times are parsed in plain HH:MM format, so there is no fiddling with AM/PM dropdowns or calendar pickers. Because it is local, it works the same on a phone, tablet, or laptop, even offline once the page has loaded.

A quick note on format: enter times as two-digit hours and minutes separated by a colon (9:30 or 09:30 both work). For day-and-date spans rather than clock times, reach for a date calculator instead. This tool is built for the hours-and-minutes question: how long was it from one time to another?