AbstractIn this article the quantum chemically calculated charge density distribution of 18‐crown‐6 and the K+ …18‐crown‐6 complex are compared with the charge density distribution of smaller molecules and corresponding complexes which can be considered as fragments of the 18‐crown‐6 molecule. An analysis of the charge density distribution in terms of atomic charge distribution according to the stockholder recipe gives accurate rules for the transferability of the charge density distribution. This gives us the possibility to construct the charge density distribution of large molecules out of accurate large basis set results on small molecules.