Time Duration Calculator
Enter your start and end time below, and this time duration calculator outputs the exact elapsed hours and minutes.
About
About Time Duration Calculator
Subtracting clock times by hand runs into trouble because time operates on a base-60 system, 60 minutes to an hour, not the base-10 math people do everything else in, so a straightforward subtraction like 2:15 minus 45 minutes requires "borrowing" across the hour boundary. A time duration calculator handles that conversion instantly, which matters for anything from tracking a work shift to timing an interval workout.
This gets genuinely error-prone the moment a shift crosses midnight, starting at 10 PM and ending at 6 AM the next day, since a naive subtraction assumes both times fall on the same calendar day. A calculator built to handle this correctly recognizes the day rollover automatically rather than returning a negative or nonsensical result.
For billing or payroll purposes, the result usually needs to be in decimal hours rather than hours and minutes separately, 7 hours and 30 minutes needs to become 7.5 for a standard hourly rate calculation to work cleanly, a conversion this tool handles as part of the output rather than something you'd calculate separately afterward.
Enter a start time and an end time, with AM or PM specified where it matters, and the elapsed duration calculates instantly, shown in both hours-and-minutes format and decimal hours.
It correctly handles a shift that crosses midnight into the next calendar day without any extra input needed, and you can toggle between standard 12-hour and 24-hour time formats depending on what you're more comfortable working in. Your schedule details stay entirely private, calculated locally.
FAQ
Frequently asked questions
Does this handle a time span that crosses midnight correctly?
Yes, it automatically recognizes when an end time falls on the following day and calculates the correct overnight duration, no manual date adjustment needed.
Can I get the result in decimal hours for billing?
Yes, the output includes a decimal hours format, like 7.5 hours instead of 7 hours 30 minutes, which is what most hourly billing or payroll calculations actually need.
Does it support 24-hour time format?
Yes, you can toggle between standard 12-hour AM/PM format and 24-hour military time, whichever fits how you're used to reading time.
Why is manual time math so easy to get wrong?
Because time runs on base-60 rather than base-10, so subtracting minutes often requires "borrowing" an hour, a step that's simple in concept but easy to fumble doing quickly by hand.
Is this usable for tracking employee shift hours?
Yes, it's fully free for that use case, with no account or sign-up required for personal or workplace use.
Are my time logs saved anywhere?
No, every calculation runs locally through client-side JavaScript. Schedule details you enter are never stored or transmitted to a server.
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