Add or Subtract Time Calculator
Add or subtract hours and minutes from a clock time, or total up a list of durations.
New time
12:15 PM
- 24-hour
- 12:15
- Day
- Same day
- Duration
- 2h 45m
Show the work
Duration in whole minutes
d = hours × 60 + minutes
2 × 60 + 45 = 165
Start (minutes after midnight) + the duration
t = start + d
570 + 165 = 735
Wrap around the 24-hour day (1,440 minutes)
time = t mod 1,440
735 mod 1,440 = 735
Minutes after midnight as a clock time
735 min after midnight = 12:15 PM
How it works
New time = start + (or −) hours × 60 + minutes, wrapped around 24 hours; a list total = sum of each h:mm entry
Questions
- How does the add or subtract time calculator work?
- New time = start + (or −) hours × 60 + minutes, wrapped around 24 hours; a list total = sum of each h:mm entry.
- What do I need to enter?
- Calculate, Start time, Operation, Hours, Minutes, Durations. Optional fields can be left blank.
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