Steel hardness converter: HB · HRC · HV · tensile
Enter a value in any scale to get the others, interpolated from the ISO 18265 / ASTM E140 table for non-alloy and low-alloy steels. Conversions are approximate (±2 HRC, ±10 HB) and apply to hardened, normalized or annealed carbon and alloy steels — not to austenitic stainless, cold-worked or cast irons.
Works without JavaScript via the table below.
Hardness conversion table for steel
| Vickers HV | Brinell HB | Rockwell HRC | Tensile Rm MPa | Rm ksi |
|---|---|---|---|---|
| 80 | 76 | — | 255 | 37.0 |
| 100 | 95 | — | 320 | 46.4 |
| 120 | 114 | — | 385 | 55.8 |
| 140 | 133 | — | 450 | 65.3 |
| 160 | 152 | — | 510 | 74.0 |
| 180 | 171 | — | 575 | 83.4 |
| 200 | 190 | — | 640 | 92.8 |
| 220 | 209 | — | 705 | 102.3 |
| 240 | 228 | 20.3 | 770 | 111.7 |
| 260 | 247 | 24.0 | 835 | 121.1 |
| 280 | 266 | 27.1 | 900 | 130.5 |
| 300 | 285 | 29.8 | 965 | 140.0 |
| 320 | 304 | 32.2 | 1030 | 149.4 |
| 340 | 323 | 34.4 | 1095 | 158.8 |
| 360 | 342 | 36.6 | 1155 | 167.5 |
| 380 | 361 | 38.8 | 1220 | 176.9 |
| 400 | 380 | 40.8 | 1290 | 187.1 |
| 420 | 399 | 42.7 | 1350 | 195.8 |
| 440 | 418 | 44.5 | 1420 | 206.0 |
| 460 | 437 | 46.1 | 1485 | 215.4 |
| 480 | 456 | 47.7 | 1555 | 225.5 |
| 500 | 475 | 49.1 | 1620 | 235.0 |
| 550 | 523 | 52.3 | 1775 | 257.4 |
| 600 | 570 | 55.2 | 1930 | 279.9 |
| 650 | 618 | 57.8 | 2090 | 303.1 |
| 700 | — | 60.1 | — | — |
| 800 | — | 64.0 | — | — |
| 900 | — | 67.0 | — | — |
Rules of thumb
- Rm ≈ 3.3 × HB (MPa) for 100–450 HB carbon/low-alloy steel; ≈ 3.45 × HB for Q&T steels at the upper end.
- HV ≈ 1.05 × HB below 400; above that use the table.
- HRC is meaningful only above ≈ 20 HRC (≈ 225 HB); use HRB below (100 HRB ≈ 240 HB ≈ 20 HRC).
- Case-hardened and nitrided surfaces are measured in HV with light loads (HV0.3–HV1); do not convert to HB.
- Austenitic stainless (304, 316) and cold-worked steel do not follow the Rm–HB relation — tensile can be 20–30 % off.
Frequently asked questions
How do you convert HRC to HB?
There is no formula, only empirical tables (ISO 18265, ASTM E140). Rough anchors for steel: 20 HRC ≈ 226 HB, 30 HRC ≈ 286 HB, 40 HRC ≈ 371 HB, 50 HRC ≈ 481 HB; Brinell is not used above about 650 HB (≈ 60 HRC) because the ball deforms.
How do you estimate tensile strength from hardness?
For carbon and low-alloy steels Rm (MPa) ≈ 3.2–3.4 × HB (or ≈ 3.3 × HV) between 100 and 450 HB — e.g. 200 HB ≈ 650 MPa, 300 HB ≈ 970 MPa. The relation weakens above 450 HB and does not hold for austenitic stainless or cold-worked steels.
Are HV and HB the same?
Nearly, below about 400: HV ≈ HB × 1.05 in the 100–400 range. Above that Vickers keeps rising linearly while Brinell flattens (ball deformation), so 60 HRC ≈ 700 HV but only ≈ 650 HB.
Why do conversion tables differ?
They are empirical and material-specific: ISO 18265 has separate tables for unalloyed/low-alloy steels, Q&T steels, cold-worked steels, tool steels and non-ferrous metals; ASTM E140 likewise. Use the table for your material class and treat conversions as ±2 HRC / ±10 HB.
Sources: ISO 18265:2013 Table A.1; ASTM E140-12b(2019) Table 1. Values interpolated linearly between table rows.