With the computational approaches -PerMM and COSMOperm (Fig. PerMM and COSMOperm), we observe a broad distribution of permeation rates from very slow permeation (logPerm ≤ -8 cm•s -1 ) to very fast permeation (logPerm ≥ -4 cm•s -1 ). This is typical for calculated methods because they have no experimental limits. We can compare the result from the experimental method with the result from the calculation, but only up to the limits of the experimental methods. Beyond these limits, there is no possibility of comparison. The permeabilities obtained by these calculated methods can be categorized as intrinsic permeabilities.