Time Duration Calculator
Calculate the exact elapsed time between two datetimes — days, hours, minutes, and seconds — including overnight and multi-day spans.
How to calculate time duration
- Enter your start date and time. Click Now to populate with the current moment.
- Enter your end date and time.
- Click Calculate Duration to see the elapsed time.
- The result shows days, hours, minutes, and seconds — plus total hours and total minutes for easy use in timesheets.
Overnight and multi-day durations
The calculator handles any time span correctly, including overnight runs (e.g. 11 PM to 6 AM the next day) and spans across multiple days. The input uses your browser's local time, so no timezone conversion is needed for same-timezone calculations.
Privacy — runs in your browser
All calculations run locally. No data is sent to any server. No signup required.
Frequently Asked Questions
Can it calculate overnight durations?
Yes — the calculator handles date changes automatically. A duration from 10:00 PM to 6:00 AM the next day correctly returns 8 hours.
What if my end time is before my start time?
The calculator shows the absolute duration and notes that the end is before the start. Useful for checking elapsed time when you accidentally swapped the dates.
How is "total hours" calculated?
Total hours is the full duration in hours as a decimal — e.g. 1 day 6 hours = 30.0 hours. This is useful for billing and timesheets that need fractional hours.