This document specifies a method for determining the indentation hardness (Shore hardness) of vulcanized or thermoplastic rubber using durometers with the following scales: — the A scale for rubbers in the normal-hardness range; — the D scale for rubbers in the high-hardness range; — the AO scale for rubbers in the low-hardness range and for cellular rubbers; — the AM scale for thin rubber test pieces in the normal-hardness range.