Time Duration Calculator
How long between two times — and what time it is after adding or subtracting hours.
How to measure or shift time
- Pick a mode — duration between two times, or add/subtract from a time.
- Enter the times on the 24-hour clock (e.g. 17:45 for 5:45 PM).
- Press Calculate. Overnight intervals are detected automatically.
- Read the breakdown — total minutes plus the hours-and-minutes split.
Frequently asked questions
How do you calculate the duration between two times?
Convert each time to minutes since midnight, subtract the start from the end, and split the result into hours and minutes. If the end time is earlier than the start, add 1,440 minutes (one full day) to cross midnight.
How long is 9:30 AM to 5:45 PM?
8 hours and 15 minutes — 495 minutes in total.
How do you calculate time across midnight?
Add 24 hours to the end time when it is earlier than the start time. From 10:00 PM to 6:30 AM: 6:30 becomes 30:30, and 30:30 − 22:00 = 8 hours 30 minutes.
How do you add hours and minutes to a time?
Add the hours and minutes separately, carrying 60 minutes into an hour, then wrap past 24:00 back to 00:00. For example, 11:30 PM + 2 hours = 1:30 AM.
What is 8 hours before 3:00 AM?
7:00 PM the previous day — subtract across midnight and the clock wraps around.
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This tool is free, with no account and no ads. If it saved you some time, consider supporting the indie dev behind it.