ISO 18265:2013 specifies the principles of the conversion of hardness values to equivalent values in other hardness scales and to estimates of tensile strength. It gives general information on the use of the conversion tables.

The conversion tables in Annexes A to G apply to unalloyed and low alloy steels and cast steel, steels for quenching and tempering, steels for cold working, high speed steels, tool steels, hardmetals, and non-ferrous metals and alloys.

Annex H gives information about the effects of changes of the test procedure in the standards specifying the hardness tests.

Converted values obtained using ISO 18265:2013 are only directly applicable to the exact material tested. For all other materials, they provide an indicator only. In all cases, the converted values are not intended as replacements for values obtained by the correct standard method. In particular, tensile strength estimates are the least reliable converted values in ISO 18265:2013.