Date to Date Calculator
Count the exact number of days between two dates, plus weeks, months, years, business days and weekends.
How it works
Enter a start and end date. If the end is earlier, we swap them automatically and let you know.
By default the end date isn't counted (like counting nights in a hotel). Tick “Include end date” to count both days.
Business days count Monday to Friday. You can also leave out the 11 US federal holidays, using their observed dates.
Formula
days
Where:
- start, end
- = The two dates, in calendar order
- weekdays
- = Days that fall Monday-Friday
Worked example
From January 1, 2026 to December 31, 2026.
That's 364 days, or 365 if you include the end date. With the end date included there are 261 weekdays; leaving out the 11 federal holidays gives 250 business days.
Measuring Tenure and Intervals
Calculating the precise duration between two dates is essential for determining employee seniority, academic term lengths, or the time elapsed since a significant historical event. This tool breaks down the interval into total days, weeks, and a combined years/months/days view to provide the most relevant data for your specific reports.
For financial and legal applications, the difference of a single day is significant. Toggling the 'include end date' option allows you to switch between 'night counting' (like hotel stays) and 'event counting' where a three-day conference spanning Friday to Sunday is counted as three full days instead of two.
Difference Between Date Tools
While the Date Calculator finds a future date based on a span, this tool focuses on the span itself. If you are asking 'How long have I been at my job?', this is the correct choice. It removes the need for mental subtraction and provides a comprehensive breakdown of the time elapsed between any two points.
This tool is superior for calculating business days specifically. It allows you to filter out weekends and all US federal holidays, which is crucial for calculating payroll periods, shipping estimates, or legal response windows that only count days when government offices and banks are open for business.
Practical Calculation Tips
A common mistake is forgetting that months have different lengths, making 'month-to-month' calculations feel inconsistent. This tool uses standard calendar logic ensuring that an interval from the 15th to the 15th is always counted as one month, regardless of whether that month has 28, 30, or 31 days.
Pay attention to the leap year count when working with large historical spans. The tool automatically includes February 29th in its total day count whenever the range crosses a leap year. This ensures that long-term tenure calculations remain perfectly accurate down to the day over several decades of time.
Frequently asked questions
Include it when you're counting days of an event that covers both dates, like a vacation from the 1st to the 5th (5 days). Leave it off for the time between two dates.