Hardness Converter Calculator

Hardness conversion is a critical concept in Materials Physics and Engineering. It involves the conversion between different hardness measures, such as Brinell Hardness (HB), Rockwell Hardness (HRC, HRB), and Vickers Hardness (HV). This is necessary because different hardness tests might be more appropriate for different materials or conditions, yet there is a need to understand the hardness equivalences across these scales. This article will delve into the formulas associated with these conversions, their applications, and the pioneers who developed these hardness scales.

Steel Hardness Conversion Calculator
Hardness Converter Calculator Results
Rockwell (HRC) =
Rockwell (HRB) =
Vickers (HV) =

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Example Formula

While there is no simple formula to convert directly between these hardness scales due to the different mechanisms of each hardness test, several empirical formulas and conversion tables exist. An example formula for converting Brinell Hardness (HB) to Rockwell Hardness (HRC) is:

HRC = 0.95HB + 11.5


  1. HRC: Represents Rockwell Hardness on the C scale, a common hardness measure for harder materials.
  2. HB: Represents Brinell Hardness, a measure of hardness obtained by pressing a hard spherical indenter into the material under a specific load.

Please note, the accuracy of these formulas can vary, and they are often used for approximate conversions between hardness scales.

Who wrote/refined the formula

The Brinell hardness test was developed by Swedish engineer Johan August Brinell in 1900. The Rockwell hardness test was invented in the 20th century by Stanley P. Rockwell, and later refined by Hugh M. Rockwell. The Vickers hardness test, meanwhile, was developed at Vickers Ltd in the United Kingdom in 1921. Various researchers and engineers have since derived formulas for approximate conversions between these hardness scales.

Real Life Application

In real-life, hardness conversion is widely used in industries dealing with materials, such as metallurgy, engineering, and manufacturing. For example, the hardness of a steel part could be measured using the Brinell hardness test, but a vendor might specify hardness in Rockwell C scale. In such scenarios, hardness conversion becomes necessary for quality control and to ensure that the material's properties meet the specifications.

Key individuals in the discipline

Johan August Brinell, Stanley P. Rockwell, and Hugh M. Rockwell have made significant contributions to the field of material hardness testing. Their methods for hardness testing are still widely used today in various industries. Similarly, the researchers at Vickers Ltd made a critical contribution by developing the Vickers hardness test, which is renowned for its versatility.

Interesting Facts

  1. The hardness of a material can greatly influence its functionality. For instance, the hardness of metal gears must be carefully controlled to prevent premature wear or failure in operation.
  2. Stanley P. Rockwell, the inventor of the Rockwell hardness test, was a metallurgist at a ball bearing company when he invented the test. He needed a fast, reliable method to evaluate the hardness of bearing races, leading to the development of the Rockwell hardness test.
  3. While hardness conversion is a practical solution, it's important to remember that different hardness tests may respond differently to the same material. That's because they each measure hardness in a slightly different way.


Hardness conversion plays a vital role in materials physics and engineering. It allows for comparisons and conversions between different hardness scales, facilitating communication and understanding across different industries and applications. While these conversions are often approximations, they provide critical insights into material properties and aid in quality control and material selection.

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