Hours Calculator
Calculate elapsed time between two clock times, in hours and minutes, decimal hours, and total minutes.
How to calculate hours between two times
Enter the beginning and end of a time range, choosing AM or PM for each. The hours and minutes calculator updates as you type. Use it to measure a trip, a study session, or any other interval shorter than a day.
Hours and minutes formula
Elapsed minutes = end time in minutes - start time in minutes
Convert each clock time to minutes after midnight. Divide the difference by 60: the whole number is hours, and the remainder is minutes. If the end is earlier, add 1,440 minutes to it before subtracting.
Decimal hours
To calculate time in hours as a decimal, divide total minutes by 60. A 95-minute interval is 1.5833 hours; 45 minutes is 0.75 hours, not 0.45.
Results use up to four decimal places, with at least two shown. Total minutes are exact; decimal hours are rounded only for display.
Overnight time calculations
When the end time is earlier than the start, it is treated as the following day. For example, 10:00 PM to 6:00 AM spans 8 hours, or 480 minutes.
Identical times with the same AM/PM selection mean zero hours. There is no automatic 24-hour assumption.
Worked examples
From 8:30 AM to 5:15 PM, the difference is 8h 45m: 8.75 hours or 525 minutes.
From 9:45 AM to 11:20 AM, 95 minutes pass. That is 1h 35m, or approximately 1.5833 hours.
Frequently asked questions
How do I enter noon or midnight?
Noon is 12:00 PM. Midnight is 12:00 AM. Selecting the wrong period can change the interval by 12 hours.
Why does an earlier end time give a positive duration?
The calculator assumes the interval crosses midnight. If that was not intended, check both clock times and their AM/PM selections.
Can I calculate a duration longer than 24 hours?
No. This tool compares clock times, not dates, and covers intervals under 24 hours. Equal start and end times give zero.
What happens when the clocks change for daylight saving time?
The result reflects the clock times entered, without a date or time zone. An interval spanning a clock change needs a separate adjustment for the hour gained or lost.