Steel Hardness Converter: HV, HBW, HRC, HRB, HK
Convert between Vickers (HV), Brinell (HBW), Rockwell C (HRC), Rockwell B (HRB), and Knoop (HK). Whether you need HRC to HV, Brinell to Rockwell C, or any of the five scales, this converter uses Vickers as the base with commonly cited approximations for steel. Conversions are material-dependent—for certification use ASTM E140 or ISO 18265. Free, runs in your browser—no sign-up required.
What is steel hardness?
Hardness is resistance to indentation. Different scales use different indenters and loads: Vickers (HV) uses a diamond pyramid, Brinell (HBW) a tungsten carbide ball, Rockwell C (HRC) and Rockwell B (HRB) diamond or ball with different loads, and Knoop (HK) a elongated diamond. There is no exact conversion between scales—relationships depend on material and range. This converter uses commonly cited approximations for steel and normalizes to HV under the hood. For certification or design, use the scale specified in your standard and refer to ASTM E140 or ISO 18265.
How steel hardness conversion works
This converter uses Vickers (HV) as the base. Each scale is given an approximate factor to HV (e.g. for steel, HV ≈ 1.05 × HBW; 1 HRC ≈ 11.4 HV in typical ranges). Your value is converted to HV using the source scale's factor, then to the target scale by dividing by that scale's factor. Because the relationships are nonlinear and material-dependent, results are approximate—use for reference and cross-check with official conversion tables when accuracy is critical.
Key hardness scales explained
Each scale measures indentation under different conditions. Approximate factors to HV (for steel) used in this converter:
Vickers (HV)
Base unit — diamond pyramid, wide load range.
SI-compatible, used for thin layers and research. This converter normalizes all scales to HV.
Brinell (HBW)
Approx: HV ≈ 1.05 × HBW (steel)
Tungsten carbide ball; common for castings and forgings. HBW replaces older HB (steel ball).
Rockwell C (HRC)
Approx: 1 HRC ≈ 11.4 HV (typical range)
Diamond cone, high load; used for hardened steel. Most common in US for heat-treated parts.
Rockwell B (HRB)
Approx: 1 HRB ≈ 3.4 HV
Ball indenter, lower load; used for softer materials (annealed steel, brass, aluminum).
Knoop (HK)
Approx: HK ≈ HV (1:1 in this converter)
Elongated diamond; used for thin coatings and brittle materials. Often close to Vickers in same range.
When to use HV vs HRC vs HBW
HRC is the most common in US for hardened steel (e.g. 55–65 HRC for tools). HV is preferred in ISO and for thin or surface-hardened layers. HBW is used for bulk hardness of castings and forgings. HRB is for softer materials. HK appears in coating and micro-indentation work. Use the scale specified in your drawing or standard; use this converter to get approximate equivalents for steel.
Who uses a steel hardness converter?
Quality and heat-treatment engineers convert between HRC and HV when specs or test equipment differ. Metallurgists and labs compare Brinell, Vickers, and Rockwell results. Purchasing and suppliers match hardness requirements across standards. Students and educators use it for materials courses. All conversions run in your browser—no data is sent to a server. For formal certification, refer to ASTM E140 or ISO 18265 conversion tables.
Common steel hardness conversions at a glance
Approximate equivalents for steel (use official tables for critical work).
| From | To | Approx formula | Example |
|---|---|---|---|
| HRC | HV | × 11.4 | 60 HRC ≈ 684 HV |
| HBW | HV | × 1.05 | 200 HBW ≈ 210 HV |
| HV | HRC | ÷ 11.4 | 500 HV ≈ 44 HRC |
Why conversions are approximate
Hardness scales use different indenters, loads, and measurement methods. The relationship between them is empirical and depends on material (steel, aluminum, etc.) and hardness range. Linear factors (e.g. 1 HRC ≈ 11.4 HV) are averages over a range; at the extremes the conversion can differ. ASTM E140 and ISO 18265 publish conversion tables by material. This converter uses fixed factors for steel as a practical reference; for certification or critical specs use the scale and tables in your standard.
Avoiding common mistakes
Don't mix HRC and HRB without converting—they use different indenters and scales (HRC for hard, HRB for softer materials). Don't assume the same conversion factor for non-steel materials (e.g. aluminum, copper). Don't use this converter alone for acceptance testing—refer to the standard (ASTM E140, ISO 18265) specified in your requirement. Report the scale you measured (e.g. "45 HRC" not just "45").
Steel Hardness Conversion FAQ
? How do I convert HRC to HV?
Multiply HRC by approximately 11.4 to get HV (for steel in typical range). So 60 HRC ≈ 684 HV. To convert HV to HRC, divide by 11.4. Use ASTM E140 or ISO 18265 for official conversions.
? What is the difference between Brinell and Vickers?
Brinell (HBW) uses a tungsten carbide ball; Vickers (HV) uses a diamond pyramid. For steel, HV ≈ 1.05 × HBW. Brinell is often used for castings and forgings; Vickers is SI-compatible and used for thin layers and research.
? When do I use Rockwell B vs Rockwell C?
Rockwell C (HRC) uses a diamond cone and is for harder materials (e.g. hardened steel, 20–70 HRC). Rockwell B (HRB) uses a ball and is for softer materials (e.g. annealed steel, brass, aluminum). Don't use HRB for very hard parts—the scale can be inaccurate.
? Are these conversions valid for aluminum or other metals?
The factors in this converter are tuned for steel. Conversion relationships differ by material (e.g. aluminum, copper). For non-steel materials use ASTM E140 or ISO 18265 conversion tables for that material.
? What is Knoop hardness used for?
Knoop (HK) uses an elongated diamond indenter and is often used for thin coatings, surface layers, and brittle materials. It can be close to Vickers in the same range; this converter uses a 1:1 approximation for HK and HV.
? Where can I find official hardness conversion tables?
ASTM E140 (Standard Hardness Conversion Tables for Metals) and ISO 18265 (Metallic materials — Conversion of hardness values) publish conversion tables by material. Use those for certification and critical specifications; this converter is for quick reference and steel approximations.