Method for press hardening of steel, wherein a steel sheet is either pre-formed cold from a hardenable steel alloy, subsequently transferred into a tool that substantially has the contour of the preformed component, and is cooled there following a preceding heating step that effects a complete austenitisation at a speed that lies above the critical hardening speed, so that a quench hardening of the preformed component is realised, or a plate made of a steel with a composition that allows press hardening is heated to a temperature above the austenitisation temperature and subsequently hot-formed in a tool and simultaneously cooled at a speed that lies above the critical hardening speed, so that hardening is brought about, wherein the hardening is effected in that the austenitic structure is transferred into a martensitic structure with > 90 vol. %, in particular > 95 vol. % martensite and residual austenite, residual ferrite and/or bainite, characterised in that the press hardness value is calculated for adjusting a desired tool to a given steel type, wherein the press hardness value PHZ is calculated from the equation PHZ press hardness value = cooling rate in the tool PHW / theoretic PH _ cooling rate PHK wherein the cooling rate in the tool is predetermined for a desired sheet metal thickness or is measured and the theoretic PH_cooling rate PHK for steel material, the dissolved boron content in its starting material of which is > 5 ppm, is calculated as follows: PHK K / s = 1750 / 28.5 ∗ C m % + 3.5 ∗ Si m % + 2.3 ∗ Mn m % − 2 ∗ Al m % + 4 ∗ Cr m % + 3 ∗ Ni m % + 25 ∗ Mo m % − 20 ∗ Nb m % − 6.3 ∧ 2.7 and for which the boron content dissolved in the starting material of < 5 ppm results as follows: PHK K / s = 2750 / 28.5 ∗ C m % + 3.5 ∗ Si m % + 2.3 ∗ Mn m % − 2 ∗ Al m % + 4 ∗ Cr m % + 3 ∗ Ni m % + 25 ∗ Mo m % − 20 ∗ Nb m % − 7.0 ∧ 1.8, wherein P, S, N are included as unavoidable contamination, wherein V m% and Ti m% are being alloyed to the same within a range of < 0.5 m%, wherein all percentage information is listed in percent by weight, wherein the following applies: PHZ < 1: no complete hardening through martensite formation guaranteed PHZ = 1: a non-deformed or pre-deformed plate can be hardened = indirect process PHZ > 1: a plate can be hot-formed in addition to the indirect process or greater resistance against plastic deformation during hardening (hot-forming suitability), wherein the reliably realisable cooling rate in the tool is measured with a desired steel composition and a desired metal sheet thickness for this metal sheet thickness, and the press hardening value is calculated from the theoretic press hardening cooling rate here, wherein the desired steel composition and the given system are suitable for an indirect press hardening process at a press hardening value of 1, and the heat-deformation can be carried out with greater safety as the press hardening value increases to a press hardening value of > 1. PHZ < 1: no complete hardening through martensite formation guaranteed PHZ = 1: a non-deformed or pre-deformed plate can be hardened = indirect process PHZ > 1: a plate can be hot-formed in addition to the indirect process or greater resistance against plastic deformation during hardening (hot-forming suitability),