Hardness Scale Converter
Convert a material hardness value between the Mohs, Vickers (HV), Brinell (HB) and Rockwell A/B/C (HRA/HRB/HRC) scales. Enter a value on any one scale and read its approximate equivalent on all the others, using standardized ASTM E140-style correlation data for steels.
Input
The scale your value is measured on. Steel conversions use ASTM E140-style data for non-austenitic steels.
Cross-scale hardness conversions are approximate and material-dependent. Values outside the standard data range are flagged and should be treated as rough estimates only.
Output
Equivalent Hardness Values
| Scale | Value |
|---|---|
| No data yet | |
Guides
The Hardness Scale Converter translates a material hardness measurement from one scale to its approximate equivalent on the others. Enter a value on any supported scale — Mohs, Vickers (HV), Brinell (HB), or Rockwell A, B or C (HRA / HRB / HRC) — and the tool fills in a table of the corresponding values on every other scale.
Why hardness scales don't convert with a formula
There is no exact equation that turns a Vickers number into a Rockwell number, or a Brinell number into Mohs. Each scale measures resistance to a different kind of indentation — a diamond pyramid, a hardened ball, a cone — under a different load. The relationship between them is empirical: it has to be measured on real specimens and tabulated.
This converter uses that tabulated approach. The Vickers, Brinell and Rockwell scales are linked through a standardized ASTM E140-style correlation table for non-austenitic steels. Every conversion pivots through Vickers: your input is interpolated to an HV value using piecewise-linear interpolation between the two nearest table rows, and that HV value is then interpolated back out to each of the other scales. Mohs is handled separately, with a log-linear mapping across the ten reference minerals (Talc = 1 up to Diamond = 10), because mineral hardness spans several orders of magnitude in Vickers terms.
How to use it
- Pick the Source Scale that matches your measurement.
- Type the Hardness Value.
- Read the equivalent values in the results table. Anything the standard data doesn't cover is shown as
—or flagged out of typical range.
You can copy the table or download it as a CSV.
Results are approximate
Please treat every converted value as an estimate. The steel correlations apply to common non-austenitic (hardened and tempered) steels; other alloys, cast irons, and non-ferrous metals can deviate significantly. The formal ASTM E140 standard specifies exact conversion procedures per material class, and a laboratory should measure hardness directly on the scale it needs rather than converting. A value shown as out of typical range is an indication that the input sits outside the region the reference data covers.
What about Shore and Knoop?
Shore (durometer) hardness measures rubbers and plastics — an entirely different material class with no valid correlation to the metal and mineral scales above, so it is deliberately omitted rather than faked. Knoop is likewise not included, because reliable Knoop correlations are load-dependent and material-specific; adding either would mean presenting invented numbers as if they were standard.
Does my data leave the browser?
No. The conversion runs entirely client-side using a built-in lookup table — nothing you enter is uploaded.