Real wages are calculated by taking nominal wage rate, dividing by the CPI and multiplying by 100.
The problem with that calculation are:
What is the nominal wage? Are you using a national average? Averages can be misleading...a national median wage would be better. Nominal wages are also sticky. There is typically a several month lag before they react to changing employment conditions.
What CPI are you using? The BLS publishes several. There is the all-inclusive CPI, but there is also a CPI-U, CPI-E, CPI-W, C-CPI-U.