Whether you need to find out how many hours and minutes are between two times, total up multiple work shifts, calculate hours across different dates, or convert a time duration into decimal hours, our Hours Calculator handles every scenario. It supports both 12-hour (AM/PM) and 24-hour clock formats, optional break deductions, and multi-shift totalling for weekly timesheet use.
Select a calculation mode below, enter your start and end times, and press Calculate to get instant results including a full breakdown in hours, minutes, and decimal format.
Hours Calculator
Choose a mode, enter your times, and press Calculate. All modes support 12-hour and 24-hour input and optional break deduction.
Enter a start time and end time on the same day to find the duration between them.
How to Calculate Hours Between Two Times
To find the number of hours between two times, convert both times to a common unit (usually minutes since midnight), subtract the start from the end, and convert the result back into hours and minutes. If the end time is earlier than the start time, the period crosses midnight and you add 24 hours to the end time before subtracting.
Duration = End Time − Start Time
Example: 5:30 PM − 8:00 AM = 9 hours 30 minutes
Overnight calculation (crosses midnight):
Duration = (End Time + 24 hours) − Start Time
Example: 2:00 AM − 10:00 PM = (2:00 AM + 24 hrs) − 10:00 PM = 4 hours
With break deduction:
Net Duration = Total Duration − Break Time
Example: 9 hrs 30 min − 30 min break = 9 hours 0 minutes
Converting Hours and Minutes to Decimal
Payroll systems, invoices, and spreadsheets often require time expressed as a decimal number rather than in hours and minutes. To convert, divide the minutes by 60 and add the result to the whole hours.
Decimal Hours = Hours + (Minutes ÷ 60)
Example: 7 hours 45 minutes = 7 + (45 ÷ 60) = 7 + 0.75 = 7.75 hours
Decimal to hours and minutes:
Hours = whole number part of the decimal
Minutes = decimal part × 60
Example: 3.25 hours = 3 hours + (0.25 × 60) = 3 hours 15 minutes
Hours in Common Time Periods
| Time Period | Hours |
|---|---|
| 1 hour | 60 minutes / 3,600 seconds |
| 1 day | 24 hours |
| 1 week | 168 hours |
| 1 month (28 days) | 672 hours |
| 1 month (29 days) | 696 hours |
| 1 month (30 days) | 720 hours |
| 1 month (31 days) | 744 hours |
| 1 month (average) | 730.5 hours |
| 1 year (365 days) | 8,760 hours |
| 1 year (366 days, leap) | 8,784 hours |
| 1 year (average) | 8,766 hours |
| 1 decade (average) | 87,660 hours |
| 1 century | 876,600 hours |
12-Hour vs 24-Hour Clock
The 12-hour clock divides the day into two periods — AM (ante meridiem, before noon) and PM (post meridiem, after noon) — each running from 1 to 12. Midnight is 12:00 AM and noon is 12:00 PM. The 24-hour clock runs from 00:00 (midnight) to 23:59 and is used internationally in transport, the military, and medical contexts to avoid any ambiguity between morning and afternoon times.
Frequently Asked Questions
How do I calculate hours worked if my shift crosses midnight?
If your shift starts before midnight and ends after midnight, the calculator handles this automatically. For example, a shift from 10:00 PM to 6:00 AM is 8 hours. The calculator detects that the end time is earlier than the start time and adds 24 hours to the end time before computing the difference. Use the Across Two Dates mode if you want to specify the exact dates to remove any ambiguity.
What is the difference between clock hours and decimal hours?
Clock hours express time in hours and minutes — for example, 7 hours 30 minutes. Decimal hours express the same duration as a single number — 7.5 hours. Decimal format is commonly used in payroll, billing, and spreadsheet calculations because it is easier to multiply by an hourly rate. The Convert Duration mode lets you switch between both formats instantly.
How do I calculate pay from hours worked?
Multiply your total hours in decimal format by your hourly rate. For example, 7.5 hours at $14.00 per hour gives $105.00. Use the Convert Duration mode, enter your hours and minutes, and add your hourly rate — the calculator will show the estimated pay automatically.
Can this calculator handle overnight shifts?
Yes. The Between Two Times mode automatically detects when the end time is before the start time and treats the period as crossing midnight. If you want to be precise about the date change, the Across Two Dates mode lets you enter separate start and end dates along with the times.
How do I calculate total hours for a weekly timesheet?
Use the Multiple Shifts mode. Add one row for each day or shift, enter the start and end times along with any break, and press Calculate. The calculator totals all entries and displays the combined hours, minutes, and decimal equivalent for the whole period.
Why is 12:00 AM midnight and not noon?
By convention, 12:00 AM refers to midnight (the start of a new day) and 12:00 PM refers to noon. This is counterintuitive because AM means “before noon” yet 12:00 AM is not before noon — it is midnight. To avoid confusion in important contexts such as travel bookings or medication schedules, it is clearer to say “12 midnight” or “12 noon” rather than 12:00 AM or 12:00 PM.