What Is an Hours Calculation?
An hours calculation finds how much time passes between two clock times, such as how long you worked in a day, how long a trip or a shift lasted, or how many hours are left until an event. It's simple for whole hours, but quickly gets fiddly with minutes, breaks and times that cross midnight.
- Hours and minutes (h:mm): the time as a clock shows it, such as 8:15 for eight hours and fifteen minutes.
- Decimal hours: the same time as a number, such as 8.25, which payroll and invoices use to multiply by an hourly rate.
- Minutes: the whole time in minutes, such as 495.
Which calculator should I use?
- Hours Calculator: the time between one start and one end, such as a single shift or appointment.
- Work Hours Calculator: a whole week of shifts, with overtime, pay and a time card to print or save as a PDF.
How to Calculate Hours Between Two Times
Subtract the start time from the end time, then take away any break:
To turn the minutes into decimal hours, divide them by 60:
- End and Start: the two clock times. A 24-hour clock makes the subtraction easier: add 12 to PM hours, so 5:30 PM is 17:30, while 12:00 AM (midnight) is 0:00 and 12:00 PM (noon) stays 12:00.
- Break: time to take off, in minutes.
- If the end time is earlier than the start, the time runs past midnight: add 24 hours to the end time first.
Example
- From 9:00 AM to 5:30 PM with a 30-minute lunch: 17:30 − 9:00 = 8:30, minus 0:30 = 8:00, or 8.00 hours.
- From 8:47 AM to 5:13 PM: 8 hours 26 minutes. The minutes in decimal are 26 ÷ 60 = 0.43, so it's 8.43 hours.
- From 10:00 PM to 6:30 AM, overnight: 6:30 + 24:00 − 22:00 = 8:30.
- From 8:07 AM to 4:53 PM, rounded to the nearest 15 minutes: the times become 8:00 AM and 5:00 PM, so it's 9:00.
Minutes to decimal hours
| Minutes | Decimal Hours | Minutes | Decimal Hours |
|---|---|---|---|
| 5 | 0.08 | 35 | 0.58 |
| 10 | 0.17 | 40 | 0.67 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.33 | 50 | 0.83 |
| 25 | 0.42 | 55 | 0.92 |
| 30 | 0.50 | 60 | 1.00 |
How to Use the Hours Calculator
"I worked from 9 AM to 5:30 PM and took a 30-minute lunch. How many hours is that, in hours and minutes and in decimal?" This calculator answers that.
Let's enter the times for this example in each box. They are already filled in when the calculator opens, so you can follow along and then change them to your own.
Pick a tab first: 12-Hour Clock for times with AM and PM, or 24-Hour Clock for times like 17:30. Each tab keeps its own times and results.
- Start Time: Enter 9:00 AM, when the time starts. On the 24-Hour Clock tab, type 09:00; you can also type 0900, or just 9 for a whole hour.
- End Time: Enter 5:30 PM, when it ends, or 17:30 on the 24-Hour Clock tab. An end time earlier than the start counts as the next day.
- Break: Enter 30, the minutes to take off. Enter 0 for none. It must be shorter than the time between start and end.
- Round Times: Choose No rounding, or the nearest 5, 6 or 15 minutes if your employer rounds clock times.
Calculate and Reset
Click Calculate to see your results. If a box has a problem, such as an empty time, the same start and end time, or a break as long as the time, a message pops up under that box instead. With the default times you get:
- Your Results: the time from start to end (8 hours 30 minutes), what's left after the break (8 hours), and the same in decimal hours and minutes.
- Hours and minutes: the headline, 8:00.
- In Decimal Hours: 8.00, for payroll or invoices.
- In Minutes: 480.
- Before the Break and Break Taken Off: 8:30 and 30 minutes.
- Work Hours Calculator link: opens the Work Hours Calculator with this day filled in on Monday, to add up the rest of the week.
- Share Results: a link that opens this calculator with your times filled in. Copy it, or share it on Facebook or X.
Click Reset to put the boxes on the tab you're using back to their defaults and show the default results again.