Combine several durations
Choose Add (+) or Subtract (−) for each row, then enter whole hours and minutes. Enter 0 if a part is empty. Add up to 20 rows and select Calculate. Try example fills three rows without calculating; Reset returns to two blank rows.
Use this for several activity durations, a total with deductions, or a negative balance. If you have start and end clock times, use the Time Duration Calculator to find each interval first.
Method and examples
NIST lists one hour as 60 minutes. Each row is converted to minutes with hours × 60 + minutes, then added or subtracted. The signed total is split into whole hours and remaining minutes.
| Durations | Exact result |
|---|---|
| 1 h 50 min + 2 h 25 min − 0 h 40 min | 3 h 35 min (215 minutes) |
| 23 h 00 min + 3 h 00 min | 26 h 00 min |
| 1 h 00 min − 2 h 30 min | −1 h 30 min (−90 minutes) |
The negative sign applies to the entire duration. A result of −1 h 30 min means minus 90 minutes. Durations longer than 24 hours keep their full hour count.
Precision and limits
Hours and minutes are nonnegative integers within each row; the operation sets the sign. Each row accepts hours from 0 to 1,000,000 and minutes from 0 to 59. The absolute result cannot exceed 1,000,000 hours. You can enter between 2 and 20 durations.
Hours, minutes and total minutes are exact. Decimal hours equal total minutes divided by 60 and are rounded to at most four decimal places. For example, 215 minutes becomes 3.5833 decimal hours. The result says when that decimal value was rounded. For conversion in either direction, use the Decimal Hours Calculator.
No dates, time zones, daylight-saving changes or employer-specific rounding rules are applied. To move a calendar date instead, use Add Days to Date.