Hardness Conversion Calculator — HRC, HV, HB
Convert a measured hardness value between Rockwell C (HRC), Vickers (HV) and Brinell (HB) scales. Results also include an approximate tensile strength for carbon and alloy steel.
Input scale
Vickers is the universal reference scale (pyramid indenter)
How does this calculator work?
Convert between Rockwell C (HRC 20–68), Vickers (HV 238–940), and Brinell (HB 226–739) hardness for carbon and alloy steel using linear interpolation of the ASTM E140 table. No single formula exists — conversions are empirical. An approximate tensile strength is also shown.
Formula
How this is calculated
Hardness scales measure resistance to permanent indentation under a defined load, but each scale uses a different indenter geometry and load — Rockwell C uses a diamond cone, Vickers a square pyramid, Brinell a hardened steel or tungsten carbide ball. Because the scales are based on different physics, conversions between them are empirical, not algebraic. ASTM standard E140 publishes reference conversion tables derived from many paired measurements on the same steel specimens.
This calculator interpolates linearly between adjacent rows of the ASTM E140 table for carbon and alloy steel (the most common engineering context). A value in one scale is located between two bracketing table rows, and the target scale values are computed by weighted linear interpolation of the neighbours. The result is close to the ASTM table values but is a smooth approximation, not a discretised lookup.
Important limitations: the conversions apply only to steel and break down for cast iron, aluminium, titanium, ceramics, and coatings. Brinell is only meaningful up to HB ~650 (above that the ball deforms). Approximate tensile strength (UTS) from the same table is for steel only and assumes standard heat treatment — treat it as an order-of-magnitude estimate. Always use the appropriate scale for the material and application.
Frequently asked questions
Vickers (HV) is the most universal because its pyramid indenter geometry gives a mathematically consistent impression regardless of hardness, and the scale covers soft metals through ceramics. Rockwell C is the most common for hardened steel; Brinell is preferred for softer or cast materials where averaging over a larger area is desirable.
The conversion table is a best-fit to paired hardness measurements made on steel specimens. Other materials deform differently under the indenter, so the same impression depth maps to different resistance. Dedicated tables exist for cast iron, aluminium alloys and brass, but a single universal formula does not.
For carbon and alloy steel, there is an empirical correlation between Brinell hardness and tensile strength: UTS (MPa) ≈ 3.45 × HB, calibrated by the ASTM E140 table. It is a rough estimate (±10–15%) and assumes standard wrought steel heat treatment.
Also known as
TG we-Calculate Editorial Team. (2026). Hardness Conversion Calculator — HRC, HV, HB [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/hardness-conversion-calculator
TG we-Calculate Editorial Team. "Hardness Conversion Calculator — HRC, HV, HB." TG we-Calculate. 2026. https://we-calculate.com/calculator/hardness-conversion-calculator.
TG we-Calculate Editorial Team, "Hardness Conversion Calculator — HRC, HV, HB," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/hardness-conversion-calculator
@misc{wecalculate_hardness_conversion_calculator, title = {Hardness Conversion Calculator — HRC, HV, HB}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/hardness-conversion-calculator}}, year = {2026}, note = {TG we-Calculate} }
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