Hardness Conversion Calculator — Brinell, Rockwell C, Rockwell B and Vickers Converter
Convert HB, HRC, HRB and HV hardness from a selected hardness value and hardness scale using scale-specific approximation formulas.
Enter the known values and review the calculated result
Input parameters
Use consistent values and select the intended engineering units.
Input hardness
Results
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Method, application and limitations
Review the calculation method, intended application and engineering assumptions before using the result in a design decision.
Formula and calculation method
HB, HRC, HRB and HV formula:
If the input hardness scale is Brinell hardness (HB):
- HB = hardness value
- HRC = (HB − 100) / 10
- HRB = 0.48 · HB + 38
- HV = 1.05 · HB
If the input hardness scale is Rockwell C hardness (HRC):
- HRC = hardness value
- HB = 5.97 · HRC² − 59.6 · HRC + 237
- HRB = 0.48 · HB + 38
- HV = 3.3 · HRC² − 22 · HRC + 190
If the input hardness scale is Rockwell B hardness (HRB):
- HRB = hardness value
- HB = 2.1 · HRB − 80
- HRC = (HB − 100) / 10
- HV = 2 · HRB
If the input hardness scale is Vickers hardness (HV):
- HV = hardness value
- HB = 0.95 · HV
- HRC = (HV − 100) / 15
- HRB = 0.48 · HB + 38
where:
- HB — Brinell hardness (—)
- HRC — Rockwell C hardness (—)
- HRB — Rockwell B hardness (—)
- HV — Vickers hardness (—)
- hardness value — input hardness value in the selected scale (—)
- hardness scale — selected input scale: HB, HRC, HRB or HV (—)
When to use this calculator
HB, HRC, HRB and HV formula:
If the input hardness scale is Brinell hardness (HB):
- HB = hardness value
- HRC = (HB − 100) / 10
- HRB = 0.48 · HB + 38
- HV = 1.05 · HB
If the input hardness scale is Rockwell C hardness (HRC):
- HRC = hardness value
- HB = 5.97 · HRC² − 59.6 · HRC + 237
- HRB = 0.48 · HB + 38
- HV = 3.3 · HRC² − 22 · HRC + 190
If the input hardness scale is Rockwell B hardness (HRB):
- HRB = hardness value
- HB = 2.1 · HRB − 80
- HRC = (HB − 100) / 10
- HV = 2 · HRB
If the input hardness scale is Vickers hardness (HV):
- HV = hardness value
- HB = 0.95 · HV
- HRC = (HV − 100) / 15
- HRB = 0.48 · HB + 38
where:
- HB — Brinell hardness (—)
- HRC — Rockwell C hardness (—)
- HRB — Rockwell B hardness (—)
- HV — Vickers hardness (—)
- hardness value — input hardness value in the selected scale (—)
- hardness scale — selected input scale: HB, HRC, HRB or HV (—)
How to interpret the result
Converted hardness is defined as the approximate equivalent hardness value in Brinell, Rockwell C, Rockwell B and Vickers scales.
The result depends on the entered hardness value and the selected hardness scale. Increasing the entered Brinell hardness increases the converted Rockwell C hardness, Rockwell B hardness and Vickers hardness. Increasing the entered Vickers hardness increases the converted Brinell hardness, Rockwell C hardness and Rockwell B hardness.
- Info — the converted values are inside the implemented limits and the conversion quality is not low.
- Warning — at least one converted value is outside the implemented limits: Rockwell C hardness < 0 or > 70, Rockwell B hardness < 20 or > 100, Brinell hardness < 50 or > 700, or Vickers hardness < 50 or > 800.
- Warning — conversion quality is low, including Brinell hardness outside 50–600, Rockwell C input below 20 or above 60, Rockwell B input below 40, or non-positive Brinell/Vickers result.
- Invalid — the hardness value is missing, non-numeric, not finite, not positive, the hardness scale is missing, or the selected hardness scale is invalid.
The result is used to compare a hardness measurement reported in one scale with approximate equivalent values in the other supported hardness scales.
Calculation example
Example:
A user has a measured Brinell hardness value and wants to estimate equivalent Rockwell C, Rockwell B and Vickers hardness values.
- Hardness value: 250
- Hardness scale: Brinell (HB)
Result: HB = 250, HRC = 15, HRB = 158, HV = 262.5.
Assumptions and limitations
- The conversion uses only the implemented approximation equations for HB, HRC, HRB and HV.
- The input hardness value must be a positive finite number.
- The selected hardness scale must be one of the supported scales: HB, HRC, HRB or HV.
- Conversion quality is high when Brinell hardness is from 100 to 400, medium when Brinell hardness is from 50 to 600, and low outside that range.
- Rockwell C input below 20 or above 60 is treated as low conversion quality.
- Rockwell B input below 40 is treated as low conversion quality.