Hardness Conversion Chart: HRC, HRB, HV, HB (ASTM E140)

A hardness conversion chart lists approximate equivalent values between Rockwell (HRC, HRB), Vickers (HV), Brinell (HB) and other scales. The tables below are from ASTM E140, the standard hardness conversion tables, including the separate table for austenitic stainless steel, which should be used for 304 and 316 instead of the general steel tables.

Rockwell C range table: ASTM E140-12b (Reapproved 2019), Table 1. Rockwell B range and austenitic stainless steel tables: Tables 2 and 5 transcribed from an earlier printing of E140; we compared Table 1 between that printing and the 2019 edition and found the values identical. Usage notes are from E140-12b (2019) Sections 1, 6 and 7.

Read this before converting

All conversions are approximate. Different hardness tests measure different combinations of material properties, so E140 says it is not possible to state confidence limits for the error in a conversion (§6.2).
Use the table for your material. Values are valid only for the materials each table names; alloy, grain structure and heat treatment all affect the result (§6.1).
Convert specification limits, not test data. E140 recommends applying conversions mainly to agreed limits and avoiding conversion of test results whenever possible (§6.3). Convert only when the material cannot be tested on the specified scale (§1.13).
Report the original reading. A converted value is reported with the measured value and scale, for example 353 HBW (38 HRC) (§7.1).
Ball indenters: most of the original data used hardened steel balls; tungsten carbide balls give slightly different results (Note 1).

Which E140 table to use

Material	E140 table
Carbon, alloy and tool steels (non-austenitic), Rockwell C range	Table 1
Carbon, alloy and tool steels (non-austenitic), Rockwell B range	Table 2
Nickel and high-nickel alloys (over 50 % Ni)	Table 3
Austenitic stainless steel plate, annealed (HRB to Brinell)	Table 5
Austenitic stainless steel sheet (Rockwell to Rockwell superficial)	Table 6

Ferritic and martensitic stainless steels (430, 410, 420) are not austenitic; duplex grades are half ferrite. For 304, 316 and other 300-series tube, Tables 1 and 2 are not the tables E140 provides for that material.

Austenitic stainless steel: HRB to Brinell (E140 Table 5)

For austenitic stainless steel plate in the annealed condition.

HRB (100 kgf, 1/16 in. ball)	Brinell HBS (3000 kgf, 10 mm ball)
100	256
99	248
98	240
97	233
96	226
95	219
94	213
93	207
92	202
91	197
90	192
89	187
88	183
87	178
86	174
85	170
84	167
83	163
82	160
81	156
80	153
79	150
78	147
77	144
76	142
75	139
74	137
73	135
72	132
71	130
70	128
69	126
68	124
67	122
66	120
65	118
64	116
63	114
62	113
61	111
60	110

Rockwell B range: HRB, HV, HB, HK (E140 Table 2)

For non-austenitic steels. “…” means no value is given in the standard.

HRB	HV	HBS	HK	HRA	HRF	HR15T	HR30T	HR45T
100	240	240	251	61.5	…	93.1	83.1	72.9
99	234	234	246	60.9	…	92.8	82.5	71.9
98	228	228	241	60.2	…	92.5	81.8	70.9
97	222	222	236	59.5	…	92.1	81.1	69.9
96	216	216	231	58.9	…	91.8	80.4	68.9
95	210	210	226	58.3	…	91.5	79.8	67.9
94	205	205	221	57.6	…	91.2	79.1	66.9
93	200	200	216	57.0	…	90.8	78.4	65.9
92	195	195	211	56.4	…	90.5	77.8	64.8
91	190	190	206	55.8	…	90.2	77.1	63.8
90	185	185	201	55.2	…	89.9	76.4	62.8
89	180	180	196	54.6	…	89.5	75.8	61.8
88	176	176	192	54.0	…	89.2	75.1	60.8
87	172	172	188	53.4	…	88.9	74.4	59.8
86	169	169	184	52.8	…	88.6	73.8	58.8
85	165	165	180	52.3	…	88.2	73.1	57.8
84	162	162	176	51.7	…	87.9	72.4	56.8
83	159	159	173	51.1	…	87.6	71.8	55.8
82	156	156	170	50.6	…	87.3	71.1	54.8
81	153	153	167	50.0	…	86.9	70.4	53.8
80	150	150	164	49.5	…	86.6	69.7	52.8
79	147	147	161	48.9	…	86.3	69.1	51.8
78	144	144	158	48.4	…	86.0	68.4	50.8
77	141	141	155	47.9	…	85.6	67.7	49.8
76	139	139	152	47.3	…	85.3	67.1	48.8
75	137	137	150	46.8	99.6	85.0	66.4	47.8
74	135	135	147	46.3	99.1	84.7	65.7	46.8
73	132	132	145	45.8	98.5	84.3	65.1	45.8
72	130	130	143	45.3	98.0	84.0	64.4	44.8
71	127	127	141	44.8	97.4	83.7	63.7	43.8
70	125	125	139	44.3	96.8	83.4	63.1	42.8
69	123	123	137	43.8	96.2	83.0	62.4	41.8
68	121	121	135	43.3	95.6	82.7	61.7	40.8
67	119	119	133	42.8	95.1	82.4	61.0	39.8
66	117	117	131	42.3	94.5	82.1	60.4	38.7
65	116	116	129	41.8	93.9	81.8	59.7	37.7
64	114	114	127	41.4	93.4	81.4	59.0	36.7
63	112	112	125	40.9	92.8	81.1	58.4	35.7
62	110	110	124	40.4	92.2	80.8	57.7	34.7
61	108	108	122	40.0	91.7	80.5	57.0	33.7
60	107	107	120	39.5	91.1	80.1	56.4	32.7
59	106	106	118	39.0	90.5	79.8	55.7	31.7
58	104	104	117	38.6	90.0	79.5	55.0	30.7
57	103	103	115	38.1	89.4	79.2	54.4	29.7
56	101	101	114	37.7	88.8	78.8	53.7	28.7
55	100	100	112	37.2	88.2	78.5	53.0	27.7
54	…	…	111	36.8	87.7	78.2	52.4	26.7
53	…	…	110	36.3	87.1	77.9	51.7	25.7
52	…	…	109	35.9	86.5	77.5	51.0	24.7
51	…	…	108	35.5	86.0	77.2	50.3	23.7
50	…	…	107	35.0	85.4	76.9	49.7	22.7
49	…	…	106	34.6	84.8	76.6	49.0	21.7
48	…	…	105	34.1	84.3	76.2	48.3	20.7
47	…	…	104	33.7	83.7	75.9	47.7	19.7
46	…	…	103	33.3	83.1	75.6	47.0	18.7
45	…	…	102	32.9	82.6	75.3	46.3	17.7
44	…	…	101	32.4	82.0	74.9	45.7	16.7
43	…	…	100	32.0	81.4	74.6	45.0	15.7
42	…	…	99	31.6	80.8	74.3	44.3	14.7
41	…	…	98	31.2	80.3	74.0	43.7	13.6
40	…	…	97	30.7	79.7	73.6	43.0	12.6

Rockwell C range: HRC, HV, HB, HK (E140 Table 1)

For non-austenitic steels. Brinell values in parentheses are outside the range recommended for Brinell testing in ASTM E10.

HRC	HV	HBS	HBW	HK	HRA	HRD	HR15N	HR30N	HR45N
68	940	…	…	920	85.6	76.9	93.2	84.4	75.4
67	900	…	…	895	85.0	76.1	92.9	83.6	74.2
66	865	…	…	870	84.5	75.4	92.5	82.8	73.3
65	832	…	(739)	846	83.9	74.5	92.2	81.9	72.0
64	800	…	(722)	822	83.4	73.8	91.8	81.1	71.0
63	772	…	(705)	799	82.8	73.0	91.4	80.1	69.9
62	746	…	(688)	776	82.3	72.2	91.1	79.3	68.8
61	720	…	(670)	754	81.8	71.5	90.7	78.4	67.7
60	697	…	(654)	732	81.2	70.7	90.2	77.5	66.6
59	674	…	634	710	80.7	69.9	89.8	76.6	65.5
58	653	…	615	690	80.1	69.2	89.3	75.7	64.3
57	633	…	595	670	79.6	68.5	88.9	74.8	63.2
56	613	…	577	650	79.0	67.7	88.3	73.9	62.0
55	595	…	560	630	78.5	66.9	87.9	73.0	60.9
54	577	…	543	612	78.0	66.1	87.4	72.0	59.8
53	560	…	525	594	77.4	65.4	86.9	71.2	58.6
52	544	(500)	512	576	76.8	64.6	86.4	70.2	57.4
51	528	(487)	496	558	76.3	63.8	85.9	69.4	56.1
50	513	(475)	481	542	75.9	63.1	85.5	68.5	55.0
49	498	(464)	469	526	75.2	62.1	85.0	67.6	53.8
48	484	451	455	510	74.7	61.4	84.5	66.7	52.5
47	471	442	443	495	74.1	60.8	83.9	65.8	51.4
46	458	432	432	480	73.6	60.0	83.5	64.8	50.3
45	446	421	421	466	73.1	59.2	83.0	64.0	49.0
44	434	409	409	452	72.5	58.5	82.5	63.1	47.8
43	423	400	400	438	72.0	57.7	82.0	62.2	46.7
42	412	390	390	426	71.5	56.9	81.5	61.3	45.5
41	402	381	381	414	70.9	56.2	80.9	60.4	44.3
40	392	371	371	402	70.4	55.4	80.4	59.5	43.1
39	382	362	362	391	69.9	54.6	79.9	58.6	41.9
38	372	353	353	380	69.4	53.8	79.4	57.7	40.8
37	363	344	344	370	68.9	53.1	78.8	56.8	39.6
36	354	336	336	360	68.4	52.3	78.3	55.9	38.4
35	345	327	327	351	67.9	51.5	77.7	55.0	37.2
34	336	319	319	342	67.4	50.8	77.2	54.2	36.1
33	327	311	311	334	66.8	50.0	76.6	53.3	34.9
32	318	301	301	326	66.3	49.2	76.1	52.1	33.7
31	310	294	294	318	65.8	48.4	75.6	51.3	32.5
30	302	286	286	311	65.3	47.7	75.0	50.4	31.3
29	294	279	279	304	64.8	47.0	74.5	49.5	30.1
28	286	271	271	297	64.3	46.1	73.9	48.6	28.9
27	279	264	264	290	63.8	45.2	73.3	47.7	27.8
26	272	258	258	284	63.3	44.6	72.8	46.8	26.7
25	266	253	253	278	62.8	43.8	72.2	45.9	25.5
24	260	247	247	272	62.4	43.1	71.6	45.0	24.3
23	254	243	243	266	62.0	42.1	71.0	44.0	23.1
22	248	237	237	261	61.5	41.6	70.5	43.2	22.0
21	243	231	231	256	61.0	40.9	69.9	42.3	20.7
20	238	226	226	251	60.5	40.1	69.4	41.5	19.6

Hardness limits in stainless tube and pipe specifications

Specification and grade	Hardness, max
ASTM A270 S2 (pharmaceutical tubing): TP304, TP304L, TP316, TP316L	B90
ASTM A270 S2: S31803 and 2205 (S32205)	C30.5
ASTM A270 S2: 2507 (S32750)	C32
ASTM A790 (duplex pipe): S31803, 2205	290 HBW / 30 HRC
ASTM A790: 2507	300 HBW / 32 HRC

Hardness limits are stated in the scale the specification uses. Test on that scale where you can; if you must compare, convert the limit with the table for the right material, and keep the original reading on the report. Grade details: duplex 2205 and 2507, 316L tube, ASTM A270 guide.

Written by Will Lee, Account Manager (Europe), TeCarve · Reviewed against ASTM / EN / ISO source documents · How we write and review our technical guides →

Frequently asked questions

Is a hardness conversion chart accurate?

Only approximately. ASTM E140 states that conversions between hardness scales are approximate and that confidence limits for the error cannot be stated, because different tests measure different combinations of properties.

Which hardness conversion table is used for 304 and 316 stainless steel?

ASTM E140 gives separate tables for austenitic stainless steel: Table 5 (HRB to Brinell for annealed plate) and Table 6 (Rockwell to Rockwell superficial for sheet). Tables 1 and 2 are for non-austenitic steels.

What Brinell hardness is HRB 90 for austenitic stainless steel?

About 192 HBS, from ASTM E140 Table 5 for austenitic stainless steel plate in the annealed condition.

How should a converted hardness value be reported?

With the original measurement and scale, for example 353 HBW (38 HRC), as described in ASTM E140 Section 7.

Hardness Conversion Chart (ASTM E140): HRC, HRB, HV, HB and Stainless Steel