Hardness Conversion
Rockwell C, Rockwell B, Vickers, and Brinell hardness converted for steel, with the approximate tensile strength.
Conversions are
correlations.
There is no formula between hardness scales.
How the conversion works
Each scale measures a different indenter under a different load, so scales relate only through tables built from measurements on real steel. This utility holds two such tables — the Rockwell C range (HRC 20–68) and the Rockwell B range (HRB 60–100) — with Vickers as the common column. Your reading is placed in the table by linear interpolation between the two nearest rows, then read across; the rows around it are shown so you can see how coarse the step is.
Where it applies, and where it does not
Non-austenitic steels only: carbon, alloy, and tool steels. Stainless 300-series, aluminium, copper alloys, and cast irons have their own tables with different values. Brinell (10 mm ball, 3000 kgf) is not reliable above about 650 HB, so it is left blank there. The tensile strength column is the approximate correlation the tables print for steel and should never replace a tensile test on a specification.
Dataset status
The rows are transcribed from the commonly reproduced approximate conversion tables and have not yet been checked line by line against the current edition of ASTM E140 or ISO 18265. That review is scheduled and any corrected value will raise the dataset version shown with each result; until it is done, treat every value as indicative and test on the scale your specification names. Inputs stay in your browser; the same four anonymous usage counts as the rest of the site apply.