Date Difference Calculator
Calculate the exact number of days, weeks, months, and years between any two dates. Includes business days.
Free Date Difference Calculator
The SmarterSources Date Difference Calculator finds the exact duration between any two dates. Whether you need to count days until a deadline, calculate business days for a project, or simply find out how many weeks are between two events, this tool delivers instant results with no sign-up required.
How the Date Difference Calculator Works
Enter a start date and an end date. The calculator computes the difference in full years, months, and remaining days. It also provides totals in days, weeks, hours, and minutes. Business days are calculated separately by looping through each day in the range and excluding Saturdays and Sundays.
Understanding Business Days
Business days (also called working days or weekdays) are Monday through Friday. The calculator excludes weekends but does not exclude public holidays, since those vary by country and region. For precise business-day calculations that include holidays, you would need to factor in your specific country's holiday calendar.
Common Uses
This calculator is commonly used for project planning (how many work days until the deadline), legal matters (counting days for statute of limitations), financial calculations (days between payment dates), event planning (how many weeks until the event), and personal milestones (days since a memorable date).
Swap Feature
Click the swap button between the date fields to instantly reverse the start and end dates. This is helpful when you enter dates in the wrong order or want to quickly see the difference from the opposite perspective.
Frequently Asked Questions
How do I calculate the number of days between two dates?
Enter a start date and an end date above. The calculator instantly shows the difference in days, weeks, months, and years, plus total business days excluding weekends.
How are business days calculated?
Business days are counted by iterating through every day in the range and including only those that fall on Monday through Friday. Saturdays and Sundays are excluded. Public holidays are not excluded since they vary by location.
Does the calculator account for leap years?
Yes. The calculator uses JavaScript Date objects which correctly handle leap years. February 29 is included in day counts whenever it falls within the selected date range.
Can I swap the start and end dates?
Yes. Click the swap button (the double arrow icon between the date fields) to instantly reverse the two dates. The calculator recalculates automatically after swapping.
What if the start date is after the end date?
The calculator always uses the earlier date as the start and the later date as the end. You can also click the swap button to correct the order.
Is my data private?
Yes. This calculator runs entirely in your browser. No dates are sent to any server, no cookies are set, and nothing is stored.