Comprehensive hardness conversion charts for Rockwell (HRA, HRB, HRC), Brinell (HB), Vickers (HV), and Knoop (HK) scales. Accurate material hardness comparisons for engineers, metallurgists, and technical professionals
Rockwell Hardness Scales (HRA, HRB, HRC)
Rockwell A Scale (HRA) to Other Scales
HRA
Brinell (HB)
Vickers (HV)
Knoop (HK)
30
304
326
338
40
444
476
494
50
614
659
684
60
815
876
910
70
1046
1122
1166
Rockwell B Scale (HRB) to Other Scales
HRB
Brinell (HB)
Vickers (HV)
Knoop (HK)
30
156
167
173
40
248
265
275
50
368
394
409
60
521
558
579
70
714
765
794
Rockwell C Scale (HRC) to Other Scales
HRC
Brinell (HB)
Vickers (HV)
Knoop (HK)
20
202
217
225
30
288
309
321
40
431
462
480
50
632
678
704
60
920
987
1024
Brinell Hardness (HB) Conversion
Brinell (HB)
Rockwell A (HRA)
Rockwell B (HRB)
Rockwell C (HRC)
Vickers (HV)
100
23.5
57
12
107
200
35
74
20
217
300
43
85
28
326
400
50
93
35
435
500
55
100
41
544
Vickers Hardness (HV) Conversion
Vickers (HV)
Rockwell A (HRA)
Rockwell B (HRB)
Rockwell C (HRC)
Brinell (HB)
200
32
65
18
187
400
45
85
30
374
600
55
95
40
561
800
63
103
48
748
1000
70
110
55
935
Knoop Hardness (HK) Conversion
Knoop (HK)
Rockwell A (HRA)
Rockwell B (HRB)
Rockwell C (HRC)
Brinell (HB)
200
30
62
17
175
400
43
82
29
350
600
53
93
39
525
800
61
101
47
700
1000
68
108
54
875
Notes on Hardness Conversion
These conversions are approximate and can vary based on material composition and testing conditions.
Different materials may have slightly different conversion characteristics.
Always verify critical measurements with direct testing when precision is crucial.
Typical Hardness Ranges for Common Materials
Copper: 35-50 HB
Aluminum Alloys: 30-100 HB
Mild Steel: 120-180 HB
Hardened Tool Steel: 55-65 HRC
Tungsten Carbide: 80-90 HRC
Diamond: 10,000 HV (Vickers)
Conversion Factors and Formulas
Precise conversions require specific formulas for each scale
Conversion accuracy depends on material properties
Interpolation can be used for values between standard measurements
