The Excel sample size workbook is linked below (both files less than 1 MB in size): 


Excel Version 2010:

Excel Version 97 - 2003:


This workbook uses macros in Visual Basic to perform the necessary calculations. Your Excel security settings may warn you about macros and ask if you wish to enable the content of this worksheet; for this workbook to function you must enable macros.

The workbook contains three sheets:

1. Sample size -- used to find sample sizes given power level, alpha level, degrees of freedom, and effect size

2. ES Conversion -- table to convert among several different effect sizes (d, r, r-squared, f, and f-squared)

3. Power -- enables one to find power level given alpha, degrees of freedom, n, and effect size.

If you have any questions, please contact me at