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HOME›Free Tools›Hardness Conversion

Convert between HV, HBW, HRC, HRB, HRA, HRD, HK and approximate tensile strength (MPa / ksi) for 8 material types. Data from ISO 18265-2004 and ASTM E140-1997. No registration — just select, enter, and convert.

Hardness Conversion Calculator

Convert Rockwell, Brinell, Vickers, Knoop and tensile strength values with fastener grade hardness reference tables.

Calculator

Material Type

ISO 18265-2004 Table A.1 / ASTM E140 Table 1

Known Hardness Scale

Rockwell C (diamond indenter, 150 kgf)

HRC Value

Valid range: 22.2 – 65.3

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Select a material, choose a scale,
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Reference Table

— Non-alloy / Low-alloy Steel

Source: ISO 18265-2004 Table A.1 / ASTM E140 Table 1. Switch material above to update this table. Dash (—) = scale not applicable at this hardness level.

HV	HBW	HRC	HRB	HRA	HRD	HK	UTS MPa	UTS ksi
80	76	—	41.0	60.7	31.5	84	270	39
85	81	—	46.5	61.8	33.7	90	285	41
90	86	—	52.0	62.8	35.7	95	300	44
95	90	—	56.5	63.8	37.5	100	315	46
100	95	—	60.5	64.7	39.1	105	330	48
105	100	—	63.5	65.5	40.5	110	345	50
110	104	—	66.5	66.4	41.9	116	360	52
115	109	—	69.0	67.2	43.1	122	375	54
120	114	—	71.0	67.9	44.1	127	390	57
125	119	—	73.0	68.7	45.2	133	405	59
130	124	—	75.0	69.4	46.2	138	420	61
135	128	—	76.5	70.0	47.1	143	435	63
140	133	—	78.0	70.7	48.0	149	450	65
150	143	—	80.5	71.9	49.6	158	480	70
160	152	—	82.5	73.1	51.1	167	510	74
170	162	—	84.5	74.2	52.5	177	540	78
180	171	—	86.5	75.3	53.8	187	570	83
190	181	—	88.0	76.2	55.0	196	600	87
200	190	—	89.5	77.2	56.1	206	630	91
210	200	—	91.0	78.1	57.2	216	660	96
220	209	—	92.5	78.9	58.2	226	690	100
230	219	—	93.5	79.7	59.1	237	720	104
240	228	—	95.0	80.5	60.0	248	755	109
250	238	22.2	—	81.2	60.8	258	785	114
260	247	24.0	—	81.9	61.5	269	820	119
270	257	25.6	—	82.6	62.2	279	855	124
280	266	27.1	—	83.2	62.9	289	890	129
290	276	28.5	—	83.8	63.5	299	925	134
300	285	29.8	—	84.4	64.1	309	960	139
310	295	31.0	—	85.0	64.7	319	995	144
320	304	32.2	—	85.5	65.2	330	1030	149
330	314	33.3	—	86.0	65.7	341	1060	154
340	323	34.4	—	86.5	66.1	352	1095	159
350	333	35.5	—	87.0	66.6	363	1125	163
360	342	36.6	—	87.5	67.1	374	1155	168
370	352	37.7	—	87.9	67.5	384	1190	173
380	361	38.8	—	88.3	68.0	395	1220	177
390	371	39.8	—	88.7	68.4	406	1255	182
400	380	40.8	—	89.1	68.7	417	1285	186
410	390	41.8	—	89.4	69.1	428	1320	191
420	399	42.7	—	89.8	69.4	439	1350	196
430	409	43.6	—	90.1	69.7	450	1380	200
440	418	44.5	—	90.4	70.0	461	1415	205
450	428	45.3	—	90.7	70.3	472	1445	210
460	437	46.1	—	91.0	70.6	483	1480	215
470	447	46.9	—	91.3	70.9	494	1510	219
480	456	47.7	—	91.5	71.1	505	1545	224
490	466	48.4	—	91.8	71.4	516	1580	229
500	475	49.1	—	92.0	71.6	527	1610	234
520	494	50.5	—	92.4	72.0	549	1675	243
540	513	51.7	—	92.8	72.4	572	1740	252
560	532	52.8	—	93.2	72.7	594	1805	262
580	551	53.9	—	93.6	73.0	617	1875	272
600	570	54.9	—	93.9	73.2	640	1950	283
620	589	55.8	—	94.2	73.4	663	—	—
640	608	56.7	—	94.5	73.6	686	—	—
660	627	57.5	—	94.7	73.7	709	—	—
680	647	58.3	—	95.0	73.9	732	—	—
700	666	59.1	—	95.2	74.0	755	—	—
720	—	59.7	—	95.4	—	778	—	—
740	—	60.4	—	95.6	—	801	—	—
760	—	61.0	—	95.8	—	825	—	—
780	—	61.6	—	96.0	—	848	—	—
800	—	62.2	—	96.2	—	871	—	—
820	—	62.7	—	96.3	—	895	—	—
840	—	63.2	—	96.5	—	918	—	—
860	—	63.6	—	96.6	—	942	—	—
880	—	64.1	—	96.8	—	965	—	—
900	—	64.5	—	96.9	—	989	—	—
920	—	64.9	—	97.0	—	1012	—	—
940	—	65.3	—	97.2	—	1035	—	—

HBW = Brinell with tungsten carbide (WC) ball, 10 mm, 3000 kgf. Values outside the formal scale definition but commonly used as estimates are shown without parentheses for readability.

Bolt & Screw Grade Hardness Reference

Quick reference for hardness ranges specified in bolt property class standards. Useful when reviewing material test reports (MTRs / mill certs).

Grade / Class	Standard	HRC	HBW	HV	Min. UTS
SAE Grade 5	SAE J429	25–34	248–331	263–354	120 ksi (827 MPa)
SAE Grade 8	SAE J429	33–39	321–382	340–409	150 ksi (1034 MPa)
ISO 8.8	ISO 898-1	22–32	245–336	—	800 MPa (116 ksi)
ISO 10.9	ISO 898-1	32–39	304–394	—	1040 MPa (151 ksi)
ISO 12.9	ISO 898-1	39–44	372–444	380–455	1220 MPa (177 ksi)
ASTM A325	ASTM F3125	24–35	248–352	—	120 ksi (827 MPa)
ASTM A490	ASTM F3125	33–38	331–388	—	150 ksi (1034 MPa)

Note: Hardness ranges above apply to the finished fastener after heat treatment. Converted values use ASTM E140 Table 1 (non-alloy steel). Always refer to the primary standard for acceptance criteria — hardness testing is an indirect verification method.

Standards & Scale Notes

ISO 18265:2004 — Metallic materials: Conversion of hardness values (European / international)
ASTM E140-1997 — Standard Hardness Conversion Tables for Metals (US)
HBW: Brinell with tungsten carbide ball (10 mm, 3000 kgf). Replaces the older "HBS" (steel ball) notation in ISO standards.
HRC valid range: approx. HV 250 (≈ 20 HRC) up to HV 940 (≈ 65 HRC).
HRB valid range: approx. HV 80 (≈ 41 HRB) up to HV 240 (≈ 100 HRB).
UTS (Rm) correlation applies to non-alloy steel only; not reliable above ~600 HBW.
Conversions use linear interpolation between table reference points — results are estimates.