Time Calculator
Last updated: August 2026
Use the Time Calculator below — enter your times, then click Calculate to get the result.
How to Add Hours, Minutes & Seconds Manually
Adding time works differently from adding ordinary numbers because minutes and seconds are base-60, not base-10. Add each unit separately, then carry over anything that reaches 60: seconds that reach 60 become one minute, and minutes that reach 60 become one hour. Here is the classic example: 1:30:25 + 2:45:55.
Seconds ≥ 60 → carry 1 minute: seconds 20, minutes 76
Minutes ≥ 60 → carry 1 hour: minutes 16, hours 4
Total = 4 hours 16 minutes 20 seconds
Another common example: 6:45 + 2:24. Add the hours (6 + 2 = 8) and the minutes (45 + 24 = 69). Since 69 minutes is over 60, carry 1 hour over: 8 + 1 = 9 hours, with 69 − 60 = 9 minutes. Total = 9 hours 9 minutes.
Time Unit Conversions
| 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 | 7 days / 168 hours |
| 1 month (average) | 30 days / 720 hours |
| 1 year (365 days) | 8,760 hours / 525,600 minutes |
Decimal Hours for Payroll & Timesheets
Payroll systems record time as decimal hours instead of hours and minutes. Divide minutes by 60 to convert: 30 minutes = 0.5 hours, 15 minutes = 0.25 hours, 45 minutes = 0.75 hours. A week of 7:30, 8:15, 8:00, 8:15 and 7:45-hour days adds up to 39:45, which is 39.75 decimal hours. Use our overtime pay calculator to turn those hours into earnings.
Frequently Asked Questions
Data sources: Time unit definitions per the International System of Units (SI), NIST time and frequency standards, and standard payroll rounding practices.
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Time Quick Facts
- 1 hour = 60 minutes
- 1 hour = 3,600 seconds
- 1 day = 86,400 seconds
- 1 week = 168 hours
- 90 minutes = 1.5 hours
- 30 minutes = 0.5 decimal hours
