How to Add and Subtract Hours and Minutes: Reconciling Timesheets
A complete practical handbook for adding and subtracting hours and minutes across multi-day work schedules and contractor timesheets.
Interactive Hours and Minutes Calculator
1. Adding Hours and Minutes Across Multiple Shifts
Carrying Over When Minutes Exceed 60
When summing shift durations manually, add the minutes and hours separately, then carry over excess minutes into hours.
Rule: Whenever minutes equal or exceed 60, divide minutes by 60. Add the quotient to total hours and retain the remainder as minutes.
Example: Shift 1 = 7h 45m. Shift 2 = 8h 35m.
• Sum hours: 7 + 8 = 15 hours.
• Sum minutes: 45 + 35 = 80 minutes.
• Normalize: 80 minutes = 1 hour and 20 minutes (80 ÷ 60 = 1 remainder 20).
• Final Total: 15 + 1 = 16 hours and 20 minutes (16h 20m).
2. Subtracting Hours and Minutes
Borrowing 60 Minutes from the Hour Column
When subtracting times where the starting minute is smaller than the subtracted minute, borrow 1 hour (60 minutes) from the hours column.
Example: Subtract 3h 45m from 8h 15m.
• Since 15 < 45, borrow 1 hour from 8: 8 hours becomes 7 hours, and 15 minutes becomes 15 + 60 = 75 minutes.
• Subtract hours: 7 - 3 = 4 hours.
• Subtract minutes: 75 - 45 = 30 minutes.
• Result: 4 hours and 30 minutes (4h 30m).