The formula problem of making perpetual calendar with excel

It is not clear which cell your formula is entered into.

“m _ day-（WEEKDAY（m _ day）- 1）+（ROW（）-5）* 7“——

M Day ... User-defined range name, which can directly refer to the cell range, and can be in number or date format.

(workday (m days)-1) ... is a borrowed day function, which returns a day of the week (Sunday = 1, Monday =2, ...), but the formula can be simplified as: WEEKDAY(m _ day, 2).

(Row()-5)* 7 ... This step is the key. By using the line number *7 and matching with the column () in the formula, each cell is increased by 1 (day) to the right, and filled down on the 7th day (the 6th day after the increase), so that the difference between the up and down rows is "7", that is, the interval between the up and down rows is one week.

Look at his drawings, the formula should be entered in the fifth line, so the date of the first line =(5-5)* 7 = 0, and the date does not increase or decrease. As the formula fills down, each row increases by 7 days.

For this formula, you should subtract 1~7 from the m_day cell that references the original data, and then add 0 ~ 7 ~ 14 ~ 2 1 ... to make the data display successive dates one by one at a given value (or date).