Hardness Converter
Note: Conversions are interpolated from common engineering reference charts and are approximate. Best used for comparison and screening, especially for metallic materials.
What this hardness converter calculator does
This hardness converter calculator helps you translate values between popular hardness scales: Rockwell C (HRC), Rockwell B (HRB), Rockwell A (HRA), Brinell (HBW), Vickers (HV), and Mohs. If you work with metals, heat treatment, machining, or quality control, this saves time when specs are listed in one scale but your process uses another.
Instead of trying to guess from a printed chart, you can enter a value, pick the source scale, and instantly view the converted target value. The tool uses linear interpolation between known data points, which gives smooth and practical engineering estimates.
Hardness scales included
Rockwell C (HRC)
Commonly used for hardened steels and tool steels. It is one of the most recognized scales in manufacturing and heat treatment documentation.
Rockwell B (HRB)
Often used for softer metals, annealed steels, copper alloys, and aluminum alloys where HRC would be less suitable.
Rockwell A (HRA)
Used for thin materials and very hard materials where different indenter/load combinations are needed.
Brinell (HBW)
Widely used in foundry work, forgings, and larger-section components. Brinell numbers are often used for approximate tensile strength estimates in carbon steels.
Vickers (HV)
A versatile micro/macro hardness method that works across a broad range of material hardness and can be used for case depth studies.
Mohs
Primarily a mineral scratch-resistance scale. It is not directly equivalent to indentation hardness methods, so conversions are very rough and should be treated as broad comparisons only.
How to use the calculator
- Enter the known hardness value.
- Choose the scale that value is currently in (From Scale).
- Choose the target scale (To Scale).
- Click Convert to see the result and equivalent Vickers value.
- Use Swap Scales if you want to reverse the conversion quickly.
How the conversion works
Hardness scales are not perfectly linear with one another. To handle this, the calculator stores a practical set of reference points for each scale and then interpolates between nearby points. This approach mirrors how engineers use standard conversion tables in daily work.
Because material composition, microstructure, and testing method can affect results, no conversion is truly exact. Think of converted values as engineering approximations that are very useful for planning, communication, and cross-checking specifications.
Best practices when using converted hardness values
- Use converted values for estimation, not final acceptance when standards require direct testing.
- Confirm critical parts using the actual required test method (e.g., Rockwell C per specification).
- Be careful when comparing different material families (tool steel vs. aluminum vs. carbide).
- For Mohs conversions, treat output as directional guidance only.
Frequently asked questions
Are these conversions exact?
No. They are interpolated approximations based on common reference chart values.
Why does the calculator show range warnings?
Each scale has practical data limits in this model. If you enter values outside those limits, the tool warns you to avoid unrealistic or unsafe extrapolation.
Can I use this for heat-treated steels?
Yes, this is one of the most common use cases. Still, final quality decisions should follow your required standard and direct test data.
Final note
A hardness converter calculator is a fast bridge between design specs, shop-floor checks, and material certification documents. Use it to move quickly, communicate clearly, and reduce mistakes when units or scales differ across teams.