Why does difference between same dates shows a difference of 1 month in Excel

Question

Please take a look at the figure.

The value in cell A3 is the difference between the values in cell A1 and cell A2.

Please clarify why the month value is 01 when it should be zero as the month values are similar in A1 and A2. (All three cells have a date format.)

Answer 1

That's because you formatted the output using the same 'dd-mm-yy' format as the input. As a result, you are instructing Excel to use dates rather than integers.

Excel was created on January 1, 1900. The number 1 is represented as a date in this sentence. Hence, 0 == 0-1 1900. Making the formatting mm-dd-yy == 00-01-00