Hardness
Conversion Table
Instantly convert between HRC, HB, HV and tensile strength (Rm). Precise results using linear interpolation based on ASTM E140.
Enter Hardness Value
Select a scale and enter a value. Equivalents in all other scales will be calculated instantly.
Enter a value to see results
Hardness Conversion Reference Table
| HRC | HB | HV | Rm (MPa) |
|---|---|---|---|
| 20 | 226 | 238 | 730 |
| 25 | 253 | 266 | 820 |
| 30 | 286 | 302 | 950 |
| 35 | 331 | 350 | 1100 |
| 40 | 371 | 392 | 1250 |
| 45 | 421 | 446 | 1450 |
| 50 | 481 | 513 | 1650 |
| 55 | — | 595 | 1900 |
| 58 | — | 650 | 2050 |
| 60 | — | 697 | 2150 |
| 63 | — | 763 | 2300 |
| 65 | — | 832 | 2450 |
* Intermediate values are calculated using linear interpolation. Table is based on ASTM E140 standard. Brinell (HB) conversion is not defined for HRC > 52.
About Hardness Scales
HRC (Rockwell C)
Measured with a 120-degree diamond cone under 150 kgf load. The most common hardness scale for hardened steels and heat-treated parts. Valid range: 20-68 HRC.
HB (Brinell)
Measured by applying 3000 kgf load with a 10mm steel or tungsten carbide ball. Ideal for castings and softer steels. HB = F / (pi*D*(D-sqrt(D^2-d^2))/2).
HV (Vickers)
Measured with a 136-degree diamond pyramid. Can be used across all hardness ranges. Also preferred for micro-hardness measurements. HV = 1.854 * F / d^2.
Rm (Tensile Strength)
The maximum stress a material can withstand before fracture (MPa). The hardness-strength relationship is empirically determined and provides an approximate value.
Linear Interpolation Method
This calculator computes intermediate values between reference points using linear interpolation. For any x value between two known points (x0, y0) and (x1, y1):
Note: Conversion values are approximate and based on standard reference tables. Actual measured values should be used for critical engineering applications.
Looking for the Right Steel Grade?
Contact our expert team to determine the right steel grade matching the hardness and strength values required for your project.
Contact UsHow do you convert between hardness scales (HRC, HB, HV)?
Conversion between Rockwell (HRC), Brinell (HB) and Vickers (HV) hardness follows the ASTM E140 / ISO 18265 tables. Example approximate values: 40 HRC ≈ 371 HB ≈ 392 HV; 30 HRC ≈ 283 HB ≈ 302 HV; 50 HRC ≈ 481 HB ≈ 513 HV. These conversions are empirical and apply mainly to steel.
Why is hardness conversion approximate?
Each hardness method uses a different indenter (diamond cone, ball, pyramid) and load, so conversion between scales is not exact but based on experimental correlation. Material, heat-treatment condition and microstructure affect the result. ASTM E140 provides standard conversion tables for steel; cast iron, stainless and non-ferrous metals need separate tables. For critical applications, measure directly in the required scale.
Hardness Conversion Table (approximate, per ASTM E140)
| HRC | HB (3000 kg) | HV | Tensile Strength (MPa) |
|---|---|---|---|
| 20 | 226 | 238 | 738 |
| 25 | 253 | 266 | 834 |
| 30 | 286 | 302 | 951 |
| 35 | 331 | 350 | 1100 |
| 40 | 371 | 392 | 1248 |
| 45 | 421 | 446 | 1421 |
| 50 | 481 | 513 | 1620 |
| 55 | 545 | 585 | 1838 |
| 60 | 613 | 697 | 2068 |
| 65 | 688 | 832 | — |
Frequently Asked Questions
What is 40 HRC in HB (Brinell)?+
About 371 HB (and ≈392 HV), per the ASTM E140 steel conversion table.
How do I convert HRC to HV?+
Use a conversion table or calculator; e.g. 45 HRC ≈ 446 HV. A standard table is used rather than a single linear formula.
Is hardness conversion exact?+
No, it is empirical. A deviation of a few points is normal and depends on material and heat treatment.
Which scale should I use?+
HRC for hardened steel, HB for soft/medium steel and castings, HV for thin sections, surfaces and hardness profiles.
What is 40 HRC in HB?+
40 HRC ≈ 371 HB ≈ 392 HV per ASTM E140 for steel; a deviation of ±3% is normal.
What is 285 HB in HRC?+
285 HB ≈ 30 HRC ≈ 302 HV. The 293–331 HB range corresponds to roughly 31–35 HRC.
Why don't hardness scales convert perfectly?+
Each test measures a different physical response (depth vs area vs rebound); conversion tables are empirical approximations from ASTM E140, valid only for carbon and alloy steels — austenitic stainless, non-ferrous metals, and case-hardened surfaces need separate correlations.
Related Products
Related Sectors
Other Tools
Steel Grades
Related Blog Posts
Technical articles, guides and industry analyses
C45 vs 42CrMo4 Steel: Carbon or Alloy — Which to Choose?
We compare C45 (1045) carbon steel with 42CrMo4 (4140) chrome-moly quenched & tempered steel by hardenability, strength, welding and cost — which to choose and when?
Quenched and Tempered Steels: EN 10083 Grades, Values and How to Choose
Quenched and tempered (Q&T) steel is the class that delivers strength and toughness together. We put the six main EN 10083 grades — C45, 25CrMo4, 42CrMo4, 39NiCrMo3, 34CrNiMo6, 51CrV4 — into one table with chemistry, section-dependent values and selection criteria.