Time Subtraction Calculator
Subtract hours and minutes from a clock time and see the resulting time, including calculations that cross midnight.
What the calculator does
Start with a clock time and subtract the requested duration. If the subtraction passes midnight, the result wraps into the preceding clock cycle.
result time = starting clock time − duration
Worked example
12:15 AM minus 30 minutes becomes 11:45 PM. The clock result is correct even though the implied calendar date would be the previous day.
Borrowing minutes by hand
When the starting minute value is smaller than the minutes being subtracted, borrow one hour as 60 minutes. For 3:10 PM minus 45 minutes, treat 3:10 as 2 hours plus 70 minutes, then subtract 45 minutes to get 2:25 PM.