The image above demonstrates a formula that calculates the number of complete weeks between two dates. Column B and column C contains random dates.
Formula in cell D3:
Copy cell D3 and paste to cells below as far as needed.
Explaining formula in cell D3
This formula works fine if the start is later than the end date, however, you get a minus sign before the number.
If you want to remove the minus sign simply use the ABS function to remove it, the formula then becomes:
Step 1 - Subtract dates
35067 - 35685 equals 618 days.
Step 2 - Divide with 7
There are seven days in a week so we need to divide the result with 7.
618/7 equals 88.28571429.
Step 3 - Round the number down
The ROUNDDOWN function rounds the number down.
ROUNDDOWN(88.28571429) and returns 88.