Estimating CASDI Tax - Wages Calculated from box 1, 2, or 3?

Hi,

Background: my employer did not provide me a W-2 and i am unable to obtain. As a result, I am calculating a reasonable estimate of my CASDI tax payment.

 

I understand that CASDI is calculated from a percentage of wages.

 

Is this typically using box 1 wages, tips and other comps or box 2 social security wages or box 3 medicare wages and tips?