Free online tool

Time Duration Calculator

Calculate hours and minutes between two clock times, including overnight periods.

Enter your values

Result

Enter the values and choose Calculate.

Total minutes
Decimal hours

Quick answer

Calculate the elapsed time between two clock times, including an interval that passes midnight.

How to use it

  1. Enter the start and end time in 24-hour format.
  2. Turn on the overnight option when the end time belongs to the next day.
  3. Calculate and review the duration in hours and minutes.

Method

Each clock time is converted to minutes after midnight. The start value is subtracted from the end value; when overnight is selected and the end is earlier, 1,440 minutes are added before subtraction.

Worked example

From 22:45 to 01:15 on the next day, the interval is 150 minutes, or 2 hours 30 minutes.

Common uses

  • Checking a work or study session
  • Planning travel and event schedules
  • Comparing start and finish times across midnight

Limitations

This is a clock-time difference, not a payroll timesheet. It does not deduct breaks, apply overtime rules, use dates or time zones, or adjust daylight-saving clock changes.

Frequently asked questions

When should I select overnight?

Select it when the finish occurs on the following calendar day, such as 22:45 to 01:15.

Why can the result be zero?

Identical start and end times represent a zero-length interval. For a full 24 hours, split the period or use dates in a date-aware tool.

Content basis and verification

· Calculations run in your browser. Check the formula and assumptions on this page, and confirm important financial, tax, medical or legal decisions against current official guidance.