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Duration calculator

Add or subtract precise durations and see the result in hours, days and milliseconds.

Exact duration2:16:15

Hours can extend beyond 24.

Days0
Hours2
Minutes16
Seconds15
Milliseconds0
Total milliseconds8175000
H:MM:SS or H:MM:SS.SSS
A leading minus sign is supported
Processed on your device

How it works & useful details

How it works & limits

Enter H:MM:SS, optionally with a sign and up to three fractional second digits, such as -1:30:00.250. Hours may exceed 24 and can contain up to nine digits. Minutes and seconds must be 00–59.

Arithmetic is exact in milliseconds. A day is always 24 hours. These are fixed durations: calendar months and timezone/DST changes are not involved. A negative result applies to the entire breakdown.

Your working space

Explore the live preview, then save a copyable text report. Inputs stay on this device and are cleared by refreshing. Dates use the Gregorian calendar, including before its historical introduction.