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Material hardness is measured with several different tests — Brinell, Rockwell C, and Vickers for metals, and the very different ordinal Mohs scale for minerals. None of these convert to each other with a simple formula, so this tool uses a standard published reference table with interpolation.
How it works
Brinell, Rockwell C, and Vickers figures follow a standard ASTM E140-style steel hardness correspondence table, interpolated between table points. Mohs hardness — an ordinal mineral scratch-hardness scale, not a quantitative indentation test — is bridged through Vickers using the widely-cited microindentation reference measurements from Broz, Cook & Whitney (American Mineralogist, 2006), and should be treated as a much rougher approximation than the metal-to-metal conversions.
- Enter value.
- Enter from scale.
- Enter to scale.
- Click Calculate to see your results.
Examples
A hardened steel part
50 Rockwell C (HRC) corresponds to approximately 481 Brinell (HB) on the standard reference table.
Who should use it
- Comparing a material spec listed in one hardness scale against equipment rated in another.
- Quick reference when reading a hardness figure from an unfamiliar scale.
Industry applications
- Metallurgy and materials engineering
- Manufacturing and quality control
- Geology (for Mohs comparisons)
Advantages
- Covers the three most common metal hardness scales plus Mohs.
- Based on standard published reference values.
Limitations
- Approximate only — not a substitute for calibrated hardness testing.
Common mistakes to avoid
- Treating any of these conversions as exact enough for engineering specification or acceptance testing — always use calibrated, direct hardness testing for that.
Best practices
- Use this for quick reference and rough comparison only; specify and verify the actual test method required for any engineering or quality-control application.
Tips
- For anything safety-critical or contractual, always specify and perform the actual required hardness test rather than relying on a converted approximation.