Productivity
Days Between Dates
Calculate the number of days, weeks, months, and years between any two dates, with option to include the end day.
About This Tool
Use this days between dates calculator to find the exact duration between two calendar dates. It computes the total elapsed calendar days, working business days (Monday through Friday), weekend days, and outputs fractional equivalent values for weeks, months, and years.
Date Calculation Logic
Days = (End Date - Start Date) in milliseconds / 86,400,000Working business days are calculated by walking the date range and excluding Saturdays and Sundays. The option to include the end day adds exactly 1 day to the final count.
Examples
Calculate Duration of a Project
Start Date: July 1, 2026; End Date: July 15, 2026
Result: 14 calendar days (10 business days, 4 weekend days).
Including End Date for Lease Term
Start Date: Jan 1, 2026; End Date: Jan 31, 2026; Include End Day: Yes
Result: Exactly 31 calendar days total.
FAQ
How are business days determined?
Business days exclude Saturdays and Sundays. They do not automatically exclude national or regional public holidays, as holiday schedules vary widely by country and jurisdiction.
Does this calculator support reverse date ranges?
Yes. If the end date is earlier than the start date, the calculator evaluates the difference and represents the output as a negative number to reflect the backwards direction.
How is a year measured in equivalent splits?
Equivalent years are computed using a standard average calendar cycle of 365.2425 days to adjust for leap years over long historical spans.