Calculated Items: Operate on specific items within a field and add new rows to your Excel PivotTables. They are best suited for analyzing individual data subsets or comparisons.

Learn Excel 365 calculated columns to enhance your data analysis skills with dynamic formulas, cross-table calculations for real-time insight ...

HOW TO: Options ribbon -> Formulas -> Calculated Fields. A dialogue box opens up where you can name a new field and then create the formula to generate this new calculated field.