Tool Steel Hardness Conversion Calculator
Enter any hardness value and the calculator returns the nearest equivalents across the Rockwell C, Rockwell B, Vickers, and Brinell scales. It is built for the readings that do not have a ready answer, such as turning a single Vickers number from a test report into HRC, or checking a Brinell supply limit against a drawing called out in Rockwell. The conversion data follow ASTM E140 for non-austenitic steels. As a quick reference point, 60 HRC is close to 697 HV and about 654 HBW.
Hardened Tool Steel / HRC Range
Use this range for hardened and tempered tool steels, including D2, A2, O1, S7, H11, H13, M2, M35, and M42. Valid input ranges: HRC 20-68, HV 238-940, HBW 226-739, HBS 226-500.
Annealed or Soft Steel / HRB Range
Use this range for annealed, normalized, or softer steel where HRC is not suitable. This range is useful when reviewing MTC hardness values or soft supply hardness. Valid input ranges: HRB 55-100, HV 100-240, HBS 100-240.
Hardness Conversions This Calculator Covers
The calculator works in both directions across five scales: Rockwell C (HRC), Rockwell B (HRB), Vickers (HV), and Brinell measured with either a tungsten carbide ball (HBW) or a steel ball (HBS). You enter the value you already have, and it returns the nearest listed equivalent on each of the other scales, so you do not need to read across a printed chart by eye.
The conversions people run here most often are the ones a single chart row cannot answer on its own. Converting Brinell to Rockwell C matters when an annealed supply limit is given in HBW but the drawing specifies HRC. Converting Vickers to Rockwell C is common when a surface or microhardness reading is reported in HV and you need the equivalent working HRC. HBW to HRC and HRB to HRC come up when a mill certificate lists one scale while your own specification uses another. Each of these is a single entry in the calculator above rather than a manual lookup.
Because soft and hardened steel are measured by different methods, the tool keeps two separate ranges. The HRC range covers hardened and tempered tool steel, and the HRB range covers annealed or normalized steel. This split prevents a low soft reading from being matched into the hardened range by mistake. As a worked example in the soft range, 95 HRB is close to 210 HV.
Which Range Should You Use?
Use the HRC range when the steel has been hardened and tempered. Use the HRB range when the steel is still soft, annealed, or normalized. This separation prevents low HB or HV values from being incorrectly matched to a hardened steel range.
Data Source and Use Limit
The calculation data are simplified from ASTM E140 hardness conversion tables for non-austenitic steels. The HRC range is based on the Rockwell C hardness range table, and the HRB range is based on the Rockwell B hardness range table. For this tool steel calculator, only the practical front-end scales are retained: HRC, HRB, HV, HBS, and HBW.
Why the values are approximate
Rockwell, Brinell, and Vickers tests use different indenters, loads, indentation shapes, and measurement principles. A value such as 60 HRC can be compared with about 697 HV, but it is not a mathematical unit conversion like millimeters to inches.
Tool steel grade, carbide distribution, heat treatment condition, surface preparation, sample thickness, and testing equipment can all affect the reading. Use the converted value for quick comparison, not for final acceptance.
Aobo Steel Supply Note
Aobo Steel supplies tool steel round bar and plate mainly in annealed condition. Final hardening and tempering should be carried out by the customer or a qualified heat-treatment facility. For bulk tool steel supply, MTC requirements, and grade selection support, contact our sales team before ordering.
Need Tool Steel Supplied in Annealed Condition?
Aobo Steel supports bulk orders of tool steel round bar and plate, with MTC per order and practical grade selection support for distributors, stockists, and industrial buyers.