Timesheet use
Use the decimal-hour result when a spreadsheet or invoice expects hours as a number. Keep the hours-and-minutes version for human-readable notes.
⏱️ Time math
Time Duration Calculator
Calculate the duration between start and end times for shifts, study blocks, travel segments, meetings and simple timesheets.
Free browser utility: Inputs are processed locally in your browser. Results are planning references; confirm payroll, legal, tax, school, or contract deadlines with the relevant official source.
Run the calculator
Formula: end time minus start time. If the end time is earlier, overnight mode treats it as the next day.
8h 30m
Also shown as decimal hours.
Planning use
For meetings, workouts, lessons and travel segments, the calculator gives a fast check without uploading calendar details or personal schedule data.
Related time and date tools
FAQ
How do I calculate time duration?
Convert both times to minutes after midnight, subtract start from end, then convert the result back into hours and minutes.
How do overnight shifts work?
When overnight mode is on, an end time earlier than the start time is treated as the next day.
Is decimal time the same as hours and minutes?
Decimal time converts minutes into a fraction of an hour. For example, 8 hours 30 minutes equals 8.5 hours.
Source snapshot: built from Omellody GSC/local proxy opportunity work, no external keyword-volume or tool-score claims. Formula and browser behavior reviewed 2026-05-19. Deployment changes are not judged in GSC until coverage reaches this date.