Time duration formula
Duration = End − Start (add 24 h if End < Start)
Decimal hours = Hours + Minutes ÷ 60
Decimal hours = Hours + Minutes ÷ 60
Example: From 9:15 AM to 5:45 PM is 8 hours 30 minutes, or 8.5 decimal hours. A night shift from 10:00 PM to 6:30 AM is also 8 hours 30 minutes. Subtracting a 30-minute break leaves 8 hours.
Minutes to decimal hours
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| 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 |
For a whole week of shifts with overtime and pay, use the hours worked calculator.
Frequently asked questions
How do I calculate hours between two times?
Convert both times to minutes after midnight, subtract, and convert back to hours and minutes. From 9:15 to 17:45 is 1,065 − 555 = 510 minutes = 8 hours 30 minutes.
What if the end time is past midnight?
If the end time is earlier than the start time, the calculator assumes the period crosses midnight and adds 24 hours. 22:00 to 06:30 is 8 hours 30 minutes.
How do I convert minutes to decimal hours?
Divide the minutes by 60. 30 minutes = 0.5 hours, 15 minutes = 0.25, 45 minutes = 0.75 and 20 minutes ≈ 0.33. Payroll systems often need decimal hours.
Does it handle AM/PM?
Your browser shows the time picker in your local format (12-hour or 24-hour). The calculation is identical either way.