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Time Calculator
Find the hours between two times, or add a duration to see when something ends.
How to use this calculator
In time between mode, enter a start time and an end time and the tool returns the gap in hours and minutes — useful for timesheets, shifts and travel. In add duration mode, enter a start time and a number of hours and minutes to add, and it tells you the finishing time, perfect for "what time will my movie end" or working out a deadline. Both modes use a 24-hour clock and correctly roll past midnight, so an end time earlier than the start is treated as the following day.
How the calculation works
Times are handled by converting them into minutes since midnight:
minutes = hours × 60 + minutes · gap = end − start (+1440 if it crosses midnight)
Once both times are in plain minutes, finding the gap is a simple subtraction, and adding a duration is a simple addition. Converting the result back — dividing by 60 for the hours and taking the remainder for the minutes — gives a readable time. Adding 1440 minutes (a full day) whenever the end falls before the start is what lets the tool handle overnight periods correctly.
A worked example
From 14:30 to 18:15: that is 870 minutes to 1095 minutes, a gap of 225 minutes, which is 3 hours 45 minutes. In add mode, starting at 20:30 and adding 2 h 15 m gives 22:45 — and adding 4 hours instead would roll past midnight to 00:30 the next day.
Frequently asked questions
How do you calculate hours between two times?
Convert both to minutes since midnight, subtract, then convert the difference back to hours and minutes.
How do I add hours to a time?
Add the duration in minutes to the start time and wrap around midnight if it passes 24 hours.
Does it handle times past midnight?
Yes — if the end is earlier than the start, it is treated as the next day.