Time Duration & Hours Calculator
Find the exact time between two clock readings or dated moments. It handles overnight shifts, subtracts breaks, converts the result to decimal hours, and totals multiple intervals for a timesheet or CSV.
Calculate one interval
All values stay in this browser.
Net duration
8 hours
Decimal hours
8.0000
Total minutes
480
Elapsed before break
8 hr 30 min
Break deducted
30 min
Multiple intervals
Add shifts, sessions or project blocks, then export a spreadsheet-ready CSV.
| Label | Start | End | Break | Net | Remove |
|---|---|---|---|---|---|
| No intervals added yet. | |||||
Combined duration
0 hours
Combined decimal hours
0.0000
Quick examples
How this calculator avoids common mistakes
Overnight is explicit. The same clock time can mean zero hours or a full 24 hours, so this page never guesses. You decide whether the end belongs to the same day or the next one.
Breaks are validated. A break cannot be negative or longer than the gross interval. Net time is calculated only after that check.
Clock time and elapsed time are separated. Dated mode uses actual timestamps, which matters across daylight-saving changes. For international times, use the Time Zone Converter so both endpoints have an explicit zone.
Frequently Asked Questions
Choose “Times only,” enter the start and end clock times, and turn on “End is on the next day.” A 10:00 PM to 6:00 AM interval then correctly becomes 8 hours instead of a negative duration.
Decimal hours express minutes as a fraction of an hour. For example, 8 hours 30 minutes is 8.5 hours. This format is useful for timesheets, billing and spreadsheets.
In “Dates and times” mode, the calculation uses real local timestamps, so a night containing a daylight-saving transition can be one hour shorter or longer. “Times only” mode performs ordinary clock arithmetic and assumes a normal day.
No. Calculations, saved rows and CSV creation happen in your browser. Reloading the page clears the interval list unless you download it first.