Guide

1. Inside your Microsoft Excel worksheet, select a cell and then type an 'Equals' (=) sign.

2. Following that, type 'Trunc' and then select it from the suggested results.

3. Add the Yearfrac function next. Simply input 'Yearfrac' and choose it from the recommended matches.

4. After that, select the cell that contains the birthdate data and then insert a 'Comma' (,).

5. Type 'Today' and select it from the suggested results. End the first part of the formula with a closing parenthesis.

6. Proceed further by inserting a 'Comma' (,) and selecting '1 Actual/Actual' from the given options.

7. Once done, add two closing parentheses and then hit the 'Enter' or 'Return' key to finally process the results.

8. After completing these steps, the age will be calculated based on the selected data in your Microsoft Excel worksheet.