Time Addition and Subtraction Calculator
Adds up or takes away times, carrying minutes and seconds correctly.
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
The formula
total seconds = hours × 3,600 + minutes × 60 + seconds
Each line is converted to seconds, added or subtracted, and converted back.
What to watch out for
Leave unused lines at zero. Minutes and seconds can be over 59. The total runs past 24 hours and can go below zero. A point means a decimal, not minutes: for 2:30 enter 2 and 30, because 2.30 hours is 2 hours 18 minutes. For a single conversion, such as hours to minutes or milliseconds to seconds, use the time converter.
Frequently Asked Questions
What is 2 hours 30 minutes plus 1 hour 45 minutes?
4:15:00, or 4 hours 15 minutes. The minutes make 75, which carries one hour.
How do I find the time 90 minutes before 08:15?
Enter 8 hours 15 minutes, then subtract 90 minutes. The answer is 6:45:00.