Metal Hardness Conversion Calculator
Enter hardness in any scale and get all equivalents: Rockwell HRC, Rockwell HRB, Vickers HV, Brinell HB, and approximate tensile strength. ASTM E140 based. Nothing uploaded.
Input
Equivalents
Learn more: converting between hardness scales
How the conversion works
There is no formula linking Rockwell, Vickers, Brinell and tensile strength. The calculator looks your value up in a table of matched readings, finds the two rows on either side of it and interpolates between them. Enter 50 HRC and it returns 513 HV, 456 HB and about 1,595 MPa (231 ksi). Enter 48 HRC and it returns 492 HV, 440 HB and about 1,538 MPa.
The scales measure different things. Rockwell measures indentation depth under a fixed load, Vickers and Brinell measure the size of an indentation made with different indenters and loads, and tensile strength comes from pulling a sample apart. A conversion table records how readings lined up on tested samples. Outside the table's range, the calculator uses its nearest end row.
How far to trust a conversion
Kemet's guide to hardness conversion says conversion tables come from empirical testing and represent statistical averages, not exact relationships. It says ASTM E140 is explicit that conversion should be used only when direct testing is not feasible, and that it gives no confidence limits for conversion errors.
The same guide says accuracy is highest in the 200 to 350 HBW range for carbon and low-alloy steels, and that deviations should be expected for other alloy types, including austenitic steels and non-ferrous metals. Treat a converted value for stainless, titanium or aluminum as a rough guide and test the material directly if the number matters.
FAQ
Can I trust the conversion for stainless steel?
Only roughly. The Kemet guide says to expect deviations for austenitic steels, so use the result as an estimate and confirm with a direct test when it matters.
Why is the HRB value sometimes blank?
Rockwell B is used for softer materials, and the table has no HRB figure for the hardest rows. The calculator leaves the field empty instead of making one up.
Is the tensile strength a guaranteed value?
No. It is a correlation, not a specification. Two batches with the same hardness reading can differ in actual tensile strength, so use it to compare materials, not as a certified property.