Excel already knows when the month ends.

Subtraction is the easiest way to count days between two dates in Excel. You can use the arithmetic operator – (minus sign) to subtract one date from another to find the number of days between them.

Microsoft Excel is a versatile program that you can use simple or highly complex tasks, and one of the features that makes Excel so useful is its formulas. However, these can be tricky. Since many ...

DATEDIF(), which means Date + Dif, is a compatibility function left over from Lotus 1-2-3 that Microsoft adopted in Excel version 2000, which is the only version that explains how this function works.