Hours Between Two Dates
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About this calculator
Calculate the total number of hours between two dates and times. Add specific times for more precision. The result includes decimal fractions for partial hours.
How it works
The calculator takes the absolute difference between the two timestamps in seconds and divides by 3,600 (the number of seconds in one hour). The result may include decimals — for example, 2.5 hours means two hours and thirty minutes. This decimal format is commonly used in payroll and time-tracking systems.
When to use this calculator
Payroll departments calculate hours worked for wage payments. Project managers track total hours spent on tasks. Travel planners compare flight durations and layover times. Parents calculate total childcare hours for tax deductions. Event organizers determine venue rental costs based on hourly rates. Truckers track driving hours for compliance with hours-of-service regulations.
Examples
A flight departing 6:00 AM and landing 2:30 PM the same day lasts 8.5 hours.
Across days: from 9:00 AM Friday to 9:00 AM Monday is exactly 72 hours (3 days × 24 hours).
Common spans in hours
How long familiar date ranges are when measured in hours:
| Date range | Hours |
|---|---|
| One week | 168 |
| One month (avg) | 730.560 |
| One year | 8,766 |
| One decade | 87,660 |
Frequently asked questions
How many hours are between two dates one week apart?
168 hours, since a week is 7 days × 24 hours.
Why is my result a decimal?
Partial hours are shown as decimals: 2.5 hours means 2 hours and 30 minutes — the same format payroll systems use.
Do I need to enter times?
No. Without times, both dates default to midnight, giving whole-day hour counts. Add start and end times for an exact result.