DIY Cost Tools
Time Duration Calculator
TIME & DATE CALCULATOR
Time Duration Calculator
Find elapsed time between two clock times and subtract an optional break.
How it works
Enter the start and end clock times, then subtract any unpaid or excluded break minutes. The overnight option rolls an earlier end time into the following day.
Formula
Gross minutes = end minutes − start minutes, adding 1,440 minutes for an overnight interval when selected. Net minutes = gross minutes − break minutes.
Worked example
From 9:15 a.m. to 5:45 p.m. is 8 hours 30 minutes. Subtracting a 30-minute break leaves 8 hours, or 8.00 decimal hours.
Important limits
- The calculator handles a single interval of no more than 24 hours.
- It does not apply employment law, rounding rules, overtime rules, or time-zone changes.
- For payroll, use the employer’s approved timekeeping policy and applicable law.
Frequently asked questions
What if the end time is after midnight?
Enter the next-day clock time and keep overnight handling selected.
Are decimal hours the same as hours and minutes?
They represent the same duration differently. For example, 7 hours 30 minutes equals 7.5 decimal hours.
Sources and review notes
Time arithmetic uses 60 minutes per hour and 1,440 minutes per 24-hour day. Last reviewed September 29, 2026.