Explanation
First, the LEN function counts total characters in the cell B5.
LEN returns the result inside of a second LEN, which counts characters without carriage returns.
The formula in the example shown will return 1 even if a cell is empty.
LEN will also count characters in numbers, but number formatting is not included.
SUBSTITUTE Function
The Excel SUBSTITUTE function replaces text in a given string by matching.
CHAR can insert characters that are hard to enter into a formula.
For example, if A1 contains “apple”, ISBLANK(A1) returns FALSE.