To find how many hours are between two times, subtract the starting time from the ending time. Convert both clock times into minutes when needed, divide the difference by 60 for decimal hours, or separate it into complete hours and remaining minutes. From 9:00 AM to 5:30 PM, there are 8 hours 30 minutes, or 8.5 hours.
Calculate elapsed hours and minutes, overnight duration, break deductions, decimal hours, and total minutes.
Eight hours 30 minutes can also be written as 8.5 decimal hours.
Formula for Hours Between Two Times
Subtract the start time from the end time to find the elapsed duration.
For a decimal-hour result, divide the difference in minutes by 60.
The Time Duration Calculator displays both hours and minutes and decimal hours.
Example: 9:00 AM to 5:30 PM
The period from 9:00 AM to 5:00 PM contains eight complete hours.
The additional time from 5:00 PM to 5:30 PM is 30 minutes.
The total is 8 hours 30 minutes, or 8.5 decimal hours.
How to Find Complete Hours
Count the whole 60-minute periods between the two times.
Any remaining minutes are recorded separately.
For example, 7:20 AM to 10:50 AM contains three complete hours and 30 extra minutes.
How to Convert Minutes into Part of an Hour
Divide the remaining minutes by 60.
Fifteen minutes equals 0.25 hours, 30 minutes equals 0.5 hours, and 45 minutes equals 0.75 hours.
Add this decimal value to the complete hours.
| Minutes | Part of an hour | Decimal |
|---|---|---|
| 15 minutes | One quarter | 0.25 hours |
| 20 minutes | One third | 0.3333 hours |
| 30 minutes | One half | 0.50 hours |
| 40 minutes | Two thirds | 0.6667 hours |
| 45 minutes | Three quarters | 0.75 hours |
Example: 7:20 AM to 10:50 AM
The elapsed duration is 3 hours 30 minutes.
Thirty minutes equal half an hour.
The decimal-hour result is therefore 3.5 hours.
Example: 1:15 PM to 6:00 PM
The elapsed duration is 4 hours 45 minutes.
Forty-five minutes equal 0.75 hours.
The total is 4.75 decimal hours.
Hours Between Times Across Midnight
Split the period at midnight or add 24 hours to the ending time.
For 10:00 PM to 6:00 AM, there are two hours before midnight and six hours afterwards.
The total is eight hours.
Treat the ending time as occurring tomorrow when the period crosses midnight.
Example: 11:30 PM to 4:15 AM
There are 30 minutes from 11:30 PM to midnight.
There are four hours 15 minutes from midnight to 4:15 AM.
The complete duration is 4 hours 45 minutes, or 4.75 hours.
Subtracting a Break
Calculate the elapsed hours before subtracting a break.
A period of nine hours with a one-hour excluded break leaves eight counted hours.
For decimal-hour calculations, convert the break to decimal hours or minutes first.
Hours Between Identical Times
The same start and end time may represent zero hours on the same day.
It may also represent 24 hours when the ending time is on the following day.
The date or next-day setting determines the intended result.
12-Hour and 24-Hour Examples
The period from 8:00 AM to 3:00 PM is the same as 08:00 to 15:00.
Both formats produce seven hours.
Using 24-hour notation can make afternoon and overnight calculations clearer.
Common Mistakes
Do not write 8 hours 30 minutes as 8.30 decimal hours.
Thirty minutes equal 0.5 hours, so the correct decimal is 8.5.
Do not ignore a midnight crossing.
Confirm whether breaks are included in the requested number of hours.
Conclusion
Subtract the start time from the end time and separate the result into complete hours and remaining minutes.
Divide total minutes by 60 when decimal hours are required.
Use the Time Duration Calculator to calculate hours between same-day or overnight times.
FAQs
How many hours are there from 9:00 AM to 5:30 PM?
There are 8 hours 30 minutes, equal to 8.5 decimal hours.
How do I convert minutes into decimal hours?
Divide the number of minutes by 60.
Is 8 hours 30 minutes equal to 8.30 hours?
No. It equals 8.5 decimal hours.
How do I calculate hours across midnight?
Add 24 hours to the ending time or split the duration at midnight.
Can I subtract a lunch break?
Yes. Calculate the elapsed duration and then subtract the break.