Hardness Conversion Calculator

Easily convert between different hardness scales such as Rockwell (HRC, HRB, HRA), Brinell (HB), Vickers (HV), and Knoop (HK).

Convert Hardness Value

Convert Hardness



Conversions between different hardness scales are often based on empirical formulas or conversion tables. This calculator makes estimated conversions between the most commonly used hardness scales.

Warning: These conversions are approximate and may not give completely accurate results, especially for very different hardness ranges or different material types. For precise applications, direct testing or reference to the material manufacturer's data is recommended.

Approximate Hardness Values for Common Materials

Material HRC HRB HB (Brinell) HV (Vickers)
Mild Steel - ~60-90 ~100-180 ~100-180
Medium Carbon Steel ~10-25 ~90-100 ~180-250 ~180-250
Stainless Steel (Annealed) - ~70-95 ~150-200 ~150-200
Hardened Steel ~40-65 - ~370-600+ ~370-800+
Aluminum Alloys - ~30-80 ~50-150 ~50-150
Rice - ~20-70 ~50-150 ~50-150
Copper - ~20-50 ~40-120 ~40-120

This table provides a general reference only. The specific alloy of the material, the heat treatment state, and the testing conditions can significantly affect the hardness values.

What is Hardness and Why is it Important?

**Hardness** is a measure of a material's resistance to indentation, scratching, or abrasion. It is a fundamental mechanical property in engineering and materials science because it provides important information about a material's strength, wear resistance, and machinability. Hardness tests can be performed by non-destructive or semi-non-destructive methods and are often used to check material quality, evaluate heat treatment effects, and make material selection.

There are many different hardness measurement scales, each using different testing methods, indenter types, and applied loads. The most common are:

Common Hardness Scales:

Why is Hardness Conversion Necessary?

Different hardness testing methods have been developed for different application areas, material types and testing conditions. However, sometimes it is necessary to know the equivalent of a hardness value measured on one scale on another. These conversions allow direct comparisons, combining data from different sources and evaluating the suitability of testing equipment.

Hardness conversion formulas are usually empirically derived and therefore their accuracy may vary depending on the type of material, heat treatment, microstructure and hardness range. Conversions can show large deviations, especially for different material classes or hardness ranges. **In critical applications, direct test results or material manufacturer's conversion tables should always be used instead of values obtained from conversion.**