Can the duration span multiple days?
Yes. Cross-midnight and multi-day intervals are supported.
Time Duration Calculator
Measure how much time passes between a start and end date-time—ideal for shifts, recordings, and schedules.
Calculate a time duration
Enter start and end date-times. End can be earlier than start to show a negative duration.
About this calculator
How to use Time Duration Calculator, plus the formulas and logic behind the results.
Tool description
The Time Duration Calculator finds the exact elapsed interval between two moments. Use it for work shifts, media length, travel legs, or any timed event that crosses hours or days.
How to use
- Enter the start date and time.
- Enter the end date and time.
- Select Calculate to view the broken-down duration and totals.
Formulas & reference
total_seconds = end − startdays = total_seconds ÷ 86,400hours/minutes/seconds = remainder after each larger unit
Duration breakdown
- Days, hours, minutes, and seconds
- Total hours and total minutes for payroll-style views
- Works across midnight and multi-day spans
Calculation logic
Both inputs are parsed as date-times, converted to Unix timestamps, and subtracted. The absolute second difference is split into days, hours, minutes, and seconds; the sign shows direction.
Times are interpreted in the server’s default timezone unless you convert zones first with the Timezone Converter.
Time Duration Calculator FAQ
Common questions about this calculator and how to use the results.
What if end is before start?
You still get a result with a negative sign to show direction.
Do seconds matter?
Yes. Seconds are included when present in the inputs.
Is this the same as business hours?
No. This counts all elapsed clock time. Use Business Days for weekday-only day counts.
How are total hours calculated?
Total hours = total seconds ÷ 3,600 (shown with decimal precision).
Does DST affect results?
If the server timezone observes DST, ambiguous local times follow PHP DateTime rules for that zone.
Can I compare only times without dates?
Use the same calendar date for both fields to compare clock times within one day.
What format should I enter?
Use the date-time picker (YYYY-MM-DD HH:MM).