Time Duration Calculator
Calculate the exact hours, minutes, and seconds between two times or dates. Supports 12-hour and 24-hour formats, overnight duration, and date spans.
Calculating Across Midnight
When your end time is earlier than your start time, the calculator automatically assumes the end time is on the following day. This makes it easy to calculate overnight shifts and late-night events.
Using Decimal Hours for Payroll
Decimal hours convert minutes into a fraction of an hour (e.g., 1:30 becomes 1.50). This format is commonly used for payroll processing, time tracking, and billing. Our calculator provides both standard and decimal formats.
Date Math Explained
When using Date & Time mode, the calculator computes the exact difference between two timestamps in milliseconds, then converts to hours, minutes, and seconds. This accounts for date boundaries automatically.
Frequently Asked Questions
To calculate time duration, subtract the start time from the end time. Convert both times to a 24-hour format, calculate the difference in hours and minutes, then format the result. If the end time falls on the next day (overnight), add 24 hours to the end time before subtracting.
Military time (also called 24-hour time) is a time format that runs from 00:00 to 23:59, eliminating the need for AM and PM designations. For example, 2:00 PM becomes 14:00, and 11:30 PM becomes 23:30. It is commonly used in aviation, healthcare, and the military to avoid ambiguity.
Yes, this calculator automatically handles overnight duration. If your end time is earlier than your start time (e.g., 11:00 PM to 2:00 AM), the calculator assumes the end time is on the following day and adds 24 hours to the calculation.