  The resistance due to the convergence from bulk to a constriction, for
example, a nanopore, is a mainstay of transport phenomena. In classical
electrical conduction, Maxwell, and later Hall for ionic conduction, predicted
this access or convergence resistance to be independent of the bulk dimensions
and inversely dependent on the pore radius, $a$, for a perfectly circular pore.
More generally, though, this resistance is contextual, it depends on the
presence of functional groups/charges and fluctuations, as well as the
(effective) constriction geometry/dimensions. Addressing the context
generically requires all-atom simulations, but this demands enormous resources
due to the algebraically decaying nature of convergence. We develop a
finite-size scaling analysis, reminiscent of the treatment of critical
phenomena, that makes the convergence resistance accessible in such
simulations. This analysis suggests that there is a "golden aspect ratio" for
the simulation cell that yields the infinite system result with a finite
system. We employ this approach to resolve the experimental and theoretical
discrepancies in the radius-dependence of graphene nanopore resistance.
