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Time duration calculator

Enter a start and end time to get the exact duration between them.

How Time duration calculator works

Time Duration Calculator finds the elapsed duration between two times of day: the start time and the end time you type. It handles overnight spans correctly, so a shift from 22:30 to 06:15 the next morning yields a duration of 7 hours and 45 minutes rather than a negative number. The calculation runs entirely in the browser; neither the times you enter nor any results leave your device.

The arithmetic converts both times to a total number of minutes from midnight. If the end time (in minutes from midnight) is less than the start time, the tool adds 24 hours (1440 minutes) to the end time before subtracting, which correctly accounts for the overnight wrap. The result is displayed in hours and minutes, and optionally as a decimal hours figure for use in time-tracking spreadsheets.

Written by Bastien Sulyan

How to use Time duration calculator, step by step

  1. Enter the start time in hours and minutes.
  2. Enter the end time in hours and minutes.
  3. If the end time is after midnight (the next day), check the 'overnight' option or simply enter the end time as-is and the tool detects the wrap automatically.
  4. Read the duration in hours and minutes, plus the decimal equivalent if shown.

Common use cases

  • A freelancer logs the start and end of a work session and needs the duration in decimal hours for an invoice.
  • A nurse or shift worker calculates the exact length of an overnight shift that spans midnight.
  • A cook times how long a dish has been in the oven from a start time to a check time.
  • A sports coach records the start and finish times of a training session and needs the total duration in hours and minutes.

Frequently asked questions

How does the tool know the end time is the next day, not the same day?

If the end time is numerically earlier than the start time (for example, start = 23:00, end = 02:00), the tool treats the end time as belonging to the next calendar day and adds 24 hours to it before subtracting. This produces the correct overnight duration of 3 hours rather than a negative result.

Can I calculate a duration longer than 24 hours?

The tool is designed for durations within a single day or overnight span (up to 24 hours). For multi-day durations, use the date-difference tool combined with this one: calculate the number of full days separately, then add the time component.

How do I get decimal hours for a timesheet?

This tool does not print decimal hours; it gives the duration as hours, minutes and seconds, plus the total in minutes and the total in seconds. Divide the total minutes by 60 when a payroll or time-tracking system wants a single decimal number: 90 minutes is 1.5 hours. The total in minutes is usually the value those systems accept directly.

Do the start and end times I enter get sent to any server?

No. The two time values are converted to minute counts and subtracted entirely within the browser. No network request is made and nothing you type here reaches any external system.

Can I include seconds in the calculation?

The standard interface works in full minutes. If the tool offers a seconds field, the duration will include seconds in the output. Otherwise, round your times to the nearest minute before entering them.

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