Excel tracks the day of the week internally as a specific number for each of the seven days.
For example, MOD(10,3) = 1.
The result of MOD carries the same sign as the divisor.
Get most recent day of week
To find the most recent day of the week (i.e. most recent Monday, Tuesday, Wednesday, etc.) with a given starting date, you can use a formula based on the MOD function. In the example shown, the formula in cell D5 is: =B5-MOD(B5-7,7) With a start date of 16-Jan-2016 in cell B6 and the target day of the week (dow) given as 7 (for Saturday), the result is 10-Jan-2015, a Saturday.
