The equation is C=2(CL)-(CP+CI)

C = crystal capacitor value

CL = load capacitance

CP = parasitic capacitance (wires, socket, traces)

CI = input capacitance (mcu itself)

So rearranging the equation, to calculate CL:

CL = (C + (CP+CI)) / 2

I am estimating that (CP+CI) is roughly 5 pf.

CL = (33pf + (5pf)) / 2 = 19pf

or is it:

CL = (66pf + (5pf)) / 2 = 36pf

Did I do this correctly or did I miss something completely?