“How many hours is that?” is the most common time question there is — for a shift, a babysitting job, a road trip or a rental. This hours calculator answers it for two clock times on the same day, for a span that runs past midnight, or for two full dates and times several days apart. You get the result in hours and minutes, in decimal hours and in minutes, with the arithmetic shown.
How to use the hours calculator
- Choose Two clock times for spans of up to 24 hours, or Two dates and times for longer periods.
- Enter the start and end. In dates mode, also pick the start and end dates.
- Optionally enter a break in minutes to subtract, such as an unpaid lunch.
- Read the hours on the tape. The timeline under it shows where the span falls on the clock.
How hours between two times are calculated
Convert both times to a 24-hour clock and subtract:
If the end time is earlier than the start time, the period crosses midnight, so 24 hours are added to the end:
With dates, every whole day between the two dates adds 24 hours, and the difference between the two clock times is added or subtracted on top. Decimal hours are hours plus minutes ÷ 60.
Worked examples
A day shift. 8:45 AM to 5:15 PM is 17:15 − 8:45 = 8:30, or 8.5 hours (510 minutes).
An overnight shift. 10:30 PM to 7:15 AM: 7:15 is earlier than 22:30, so (7:15 + 24:00) − 22:30 = 8:45, which is 8.75 hours.
A weekend. Friday 6:00 PM to Sunday 2:30 PM: two calendar days give 48 hours, and 14:30 − 18:00 = −3:30, so the total is 48:00 − 3:30 = 44:30, or 44.5 hours.
Common time spans
| From | To | Hours : minutes | Decimal hours |
|---|---|---|---|
| 9:00 AM | 5:00 PM | 8:00 | 8.00 |
| 8:30 AM | 5:00 PM | 8:30 | 8.50 |
| 7:00 AM | 3:30 PM | 8:30 | 8.50 |
| 6:00 AM | 2:45 PM | 8:45 | 8.75 |
| 11:00 AM | 7:20 PM | 8:20 | 8.33 |
| 3:00 PM | 11:30 PM | 8:30 | 8.50 |
| 11:00 PM | 7:00 AM | 8:00 | 8.00 |
| 7:00 PM | 7:00 AM | 12:00 | 12.00 |
Mistakes to avoid
Subtracting on a 12-hour clock
5:15 − 8:45 makes no sense until 5:15 PM is written as 17:15. Converting to 24-hour time first removes most errors; the military time converter does that in one step.
Treating minutes as decimals
Eight hours and 20 minutes is 8.33 hours, not 8.20. Use the time to decimal calculator whenever you need to multiply hours by a pay rate.
Borrowing across the hour
When the end minutes are smaller than the start minutes, borrow 60 minutes from the hours: 5:10 − 2:40 becomes 4:70 − 2:40 = 2:30.
Forgetting daylight saving time
On the night clocks spring forward, a 10 PM to 6 AM shift lasts only 7 real hours; in the fall it lasts 9. Payroll rules on which figure to pay vary, so check your employer’s policy for those two nights.
Related tools
To total several shifts in one go, use the work hours calculator. For a full pay week with overtime, the time card calculator adds every day and applies the FLSA 40-hour rule.
Frequently asked questions
How many hours are between 9 AM and 5 PM?
Eight hours. Subtract the start from the end on a 24-hour clock: 17:00 − 9:00 = 8:00. If you take a 30-minute unpaid lunch, you worked 7 hours 30 minutes, or 7.5 decimal hours.
How do I calculate hours that go past midnight?
Add 24 hours to the end time before subtracting. From 10:30 PM to 7:15 AM: (7:15 + 24:00) − 22:30 = 8:45. The calculator does this automatically whenever the end time is earlier than the start time.
What if the start and end times are the same?
In two-times mode the calculator reads equal times as a full 24-hour span, such as a 24-hour on-call shift from 7:00 AM to 7:00 AM. Switch to dates and times if you mean zero hours or several days.
How do I turn the result into decimal hours?
Divide the minutes by 60 and add the hours. 8 hours 45 minutes is 8 + 45 ÷ 60 = 8.75 hours. The tape always shows the decimal figure next to the hours and minutes.
Does the dates mode account for daylight saving time?
No. It counts every calendar day as 24 hours, which matches how most payroll and scheduling tools count. A span that crosses a daylight saving change is really one hour shorter (in March) or longer (in November).