How to Add Time Durations
Adding times manually requires carrying values — 60 seconds become a minute, 60 minutes become an hour. This calculator handles all the carrying automatically.
Manual Method
- Add seconds. If the total is 60 or more, subtract 60 and carry 1 to minutes.
- Add minutes (plus any carry). If 60 or more, subtract 60 and carry 1 to hours.
- Add hours (plus any carry).
Example
Add 2:48:30 + 4:17:45:
- Seconds: 30 + 45 = 75 → write 15, carry 1
- Minutes: 48 + 17 + 1 = 66 → write 06, carry 1
- Hours: 2 + 4 + 1 = 7
- Result: 7:06:15
Decimal Hours Conversion
| Minutes | Decimal |
|---|---|
| 5 min | 0.08 |
| 10 min | 0.17 |
| 15 min | 0.25 |
| 20 min | 0.33 |
| 30 min | 0.50 |
| 45 min | 0.75 |
Common Uses
- Timesheet totals: Sum daily work hours for weekly payroll.
- Exercise tracking: Add up workout durations across multiple sessions.
- Travel planning: Total flight times including layovers.
- Project management: Sum task durations for total project time.
- Cooking: Add prep time, cook time, and rest time for total recipe duration.
- Music/video production: Calculate total runtime of tracks or clips.
Time Units Reference
| Unit | Equivalent |
|---|---|
| 1 minute | 60 seconds |
| 1 hour | 60 minutes / 3,600 seconds |
| 1 day | 24 hours / 1,440 minutes / 86,400 seconds |
| 1 week | 168 hours / 10,080 minutes |
| Standard work week | 40 hours / 2,400 minutes |
Tips for Accurate Time Tracking
- Round to the nearest quarter hour (15 min) for simple payroll — use exact times for billing.
- When adding many small durations, seconds add up fast. Always include them for accuracy.
- Decimal hours are easier for multiplication (e.g., 7.5 hours × $25/hr = $187.50).