Time Calculator
Add or subtract hours, minutes, and seconds. Useful for calculating worked hours, overtime, and project time.
First Time
h
min
sec
Second Time
h
min
sec
Result
4h 15m 30s
Total seconds
15330
Total minutes
255
Decimal hours
4.2583
How to Use This Calculator
Enter hours, minutes, and seconds for each time value. Select whether to add or subtract. The result is shown in hours, minutes, seconds along with total seconds, total minutes, and decimal hours for payroll and billing calculations.
The Formula
Convert to seconds:
Total Seconds = (Hours × 3600) + (Minutes × 60) + Seconds
Add: Result = Time1 + Time2 (in seconds)
Subtract: Result = Time1 − Time2 (in seconds)
Convert back:
Hours = floor(Result ÷ 3600)
Minutes = floor((Result mod 3600) ÷ 60)
Seconds = Result mod 60
Decimal Hours = Total Seconds ÷ 3600
Example
2h 30m 0s + 1h 45m 30s
Time 1 in seconds9,000
Time 2 in seconds6,330
Total seconds15,330
Result4h 15m 30s
Decimal hours4.2583 hours
FAQ
Add your worked hours using this calculator to get total hours in decimal format. Then multiply by your hourly rate. For example: regular 8h + overtime 2h 30m = 10.5 hours total. At ₦1,500/hour that's ₦15,750. Nigerian labour law requires overtime pay at 1.25× the normal rate for hours beyond 8 per day or 40 per week.
Decimal hours make multiplication easy. 4h 15min = 4.25 hours. Multiplying 4.25 × hourly rate is straightforward. In contrast, multiplying 4h 15min directly requires separate handling of hours and minutes. Payroll software, timesheet templates, and billing systems all use decimal hours.
Use the calculator sequentially — add the first two times, then enter the result as the first time and add the third value. Alternatively, convert each time to total seconds manually, sum them, then convert back: 1h30m = 5400s; 2h15m = 8100s; 0h45m = 2700s. Total = 16200s = 4h30m.