Steel Hardness Conversion Table

Note that hardness conversions are approximate only as the different scales use different methods of testing

Brinell

Brinell

Vickers

Rockwell

Rockwell

Impression

Hardness

hardness

Hardness

Hardness

Equiv Rm

Equiv Rm

Equiv Rm

Dia. mm

HB

HV

B

C

tonf/in²

kgf/mm²

N/mm²

2.50

601

640

57.0

2.55

578

615

56.0

2.60

555

591

120

54.5

2.65

534

569

119

53.5

2.70

514

547

119

52.0

2.75

495

528

117

51.0

2.80

477

508

117

49.5

2.85

461

491

116

48.5

101

160

1569

2.90

444

474

115

47.0

98

155

1520

2.95

429

455

115

45.5

95

150

1471

3.00

415

440

114

44.5

92

145

1422

3.05

401

425

113

43.0

88

139

1363

3.10

388

410

112

42.0

85

134

1314

3.15

375

396

112

40.5

82

129

1265

3.20

363

383

110

39.0

80

126

1236

3.25

352

372

110

38.0

77

121

1187

3.30

341

360

109

36.5

75

118

1157

3.35

331

350

109

35.5

73

114

1118

3.40

321

339

108

34.5

71

111

1089

3.45

311

328

108

33.0

68

107

1049

3.50

302

319

107

32.0

66

104

1020

3.55

293

309

106

31.0

64

101

990

3.60

285

301

105

30.0

63

99

971

3.65

277

292

104

29.0

61

96

941

3.70

269

284

104

27.5

59

93

912

3.75

262

276

103

26.5

58

91

892

3.80

255

269

102

25.5

56

89

873

3.85

248

261

102

24.0

55

87

853

3.90

241

253

100

23.0

53

84

824

3.95

235

247

99

22.0

51

81

794

4.00

229

241

98

20.5

50

79

775

4.05

223

235

97

49

77

755

4.10

217

228

96

48

76

745

4.15

212

223

96

46

73

716

4.20

207

218

95

45

71

696

4.30

197

208

93

43

68

667

4.40

187

197

91

41

65

637

4.50

179

189

89

39

62

608

4.60

170

179

87

36

57

559

4.70

163

172

85

35

55

539

4.80

156

165

83

34

54

530

4.90

149

157

81

32

51

500

5.00

143

150

79

31

49

481

5.10

137

144

77

31

49

481

5.20

131

138

74

30

47

461

5.30

126

133

72

29

46

451

5.40

121

127

70

28

44

431

5.50

116

122

68

27

43

422

5.60

111

117

66

26

41

402

5.70

107

113

64

25

39

382

5.80

103

108

61

24