Time Duration Calculator
Hours and minutes between two times (supports overnight shifts)
How this calculator works
Enter a start time and end time. The calculator converts both into minutes since midnight and computes the difference. The result is displayed as hours and minutes, total minutes, and decimal hours (for timesheets).
- 12h / 24h formats — Choose between AM/PM style (12-hour) or military time (24-hour). Both produce identical results.
- Overnight mode — When enabled, an end time earlier than the start time is treated as the next day (useful for night shifts).
- Signed result — See negative durations when end is before start on the same day.
Common use cases
- Work hours — Calculate how many hours you worked today (9 AM to 5:30 PM = 8h 30m).
- Night shifts — Overnight workers can find shift length (10 PM to 6 AM = 8 hours).
- Timesheets — Convert to decimal hours for payroll export (8h 30m = 8.5 hours).
- Meeting length — How long was that conference call?
- Travel planning — Duration between departure and arrival times.
Examples
Standard workday
09:00 → 17:30 = 8h 30m (8.5 decimal)
Overnight shift
22:00 → 06:00 (next day) = 8h 0m
Short meeting
14:00 → 14:45 = 0h 45m (0.75 decimal)
12-hour format
9:00 AM → 5:30 PM = 8h 30m
Understanding decimal hours
Decimal hours are commonly used in timesheets and payroll systems. To convert, divide total minutes by 60:
| Duration | Minutes | Decimal |
|---|---|---|
| 8h 30m | 510 | 8.50 |
| 7h 45m | 465 | 7.75 |
| 4h 15m | 255 | 4.25 |
| 0h 45m | 45 | 0.75 |
Frequently Asked Questions
What if the end time is earlier than the start time?▼
Enable "Assume next day if end is earlier" (overnight mode) to treat the end time as occurring on the next day. This is useful for overnight shifts like 10 PM to 6 AM. If disabled and "Show signed result" is on, the result will be negative.
How do I calculate overnight shift hours?▼
Enter the start time (e.g., 22:00 or 10:00 PM), enter the end time (e.g., 06:00 or 6:00 AM), and make sure "Overnight" mode is enabled in Options. The calculator will treat the end time as the next day and return the correct duration (8 hours in this example).
Is this tool timezone-aware or DST-aware?▼
No. This is a pure clock-time calculation (hours and minutes). It does not consider time zones, daylight saving time transitions, or specific dates. For timezone conversions, use a dedicated time zone converter.
How is decimal hours calculated?▼
Decimal hours = total minutes / 60. For example, 8 hours 30 minutes = 510 minutes / 60 = 8.5 decimal hours. This format is commonly used in timesheets and payroll systems.
Why would I need a signed (negative) result?▼
Signed results are useful when you want to see that an end time is actually earlier than a start time on the same day. For example, 5:00 PM to 9:00 AM (same day) = -8 hours, indicating the end is 8 hours before the start.
What is the difference between 12h and 24h mode?▼
12-hour mode uses 1-12 hours with AM/PM (common in USA, UK). 24-hour mode uses 00-23 hours without AM/PM (common in Europe, military time). Both give the same results; pick whichever you find easier.
Can I use this for multiple time segments?▼
This calculator handles one start-to-end segment at a time. For multiple segments (like break times), calculate each segment separately and add them together, or use a full timesheet calculator.
How accurate is the result?▼
The result is exact to the minute. Seconds are not included in the calculation. For most shift/work-hour calculations, minute-level precision is sufficient.