Free · Instant calculations
Date Difference Calculator
Count days and weeks between two dates, optionally including the end date.
How to use this tool
Choose the calculation method, enter your values and select Calculate. Reset clears results and restores the example inputs.
Formula
Days = end date − start date; add one for an inclusive range. Weeks = days ÷ 7.
Example
1 to 18 September is 17 days, or 18 with the end date included.
Assumptions and limits
Calendar days only; weekends and holidays are included. The end date must follow the start date.
Frequently asked question
Does this count business days? No. It counts every calendar day.