The Brinell test presses a hard ball into a material and measures the round dent. Softer materials take a bigger dent. It is widely used for castings, forgings and soft metals where a large indent averages out the grain structure.
How to use the Brinell Hardness Number Calculator
- Applied load P
- Indenter diameter D
- Indentation diameter d
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Enter the test force, the ball diameter (usually 10 mm) and the mean diameter of the indentation.
Inputs explained
| Field | What to enter |
|---|---|
| Applied load P | Units: kgf, N, kN |
| Indenter diameter D | Units: mm, cm, m, in, µm |
| Indentation diameter d | Units: mm, cm, m, in, µm |
What each result means
- Indentation surface area = pi×[D]×([D] – sqrt([D]^2 – [d]^2))÷2
- Brinell hardness number = [Applied load P]÷[Indentation surface area]
- Approximate tensile strength (steels) = 3.45×[Brinell hardness number]
Example values
How the main result changes when Applied load P changes and everything else stays at the example values above:
| Applied load P (kgf) | Brinell hardness number (HBW) |
|---|---|
| 1,500 | 114.3836 |
| 2,250 | 171.5754 |
| 3,000 | 228.7671 |
| 3,750 | 285.9589 |
| 4,500 | 343.1507 |
| 6,000 | 457.5343 |
Formula
HBW = 2P / (π·D·(D − √(D² − d²))) (P in kgf, D and d in mm)
Worked example
Inputs — Applied load P: 3,000 kgf; Indenter diameter D: 10 mm; Indentation diameter d: 4 mm.
Results — Indentation surface area = 13.1138 mm²; Brinell hardness number = 228.7671 HBW; Approximate tensile strength (steels) = 789 MPa.
Key terms
- Indentation hardness
- Resistance to permanent indentation.
Frequently asked questions
What does HBW mean?
Brinell hardness measured with a tungsten carbide ball.
What load is standard?
3,000 kgf with a 10 mm ball for steels and cast iron.
Why should d be between 0.24D and 0.6D?
Outside that range results are less reliable.
How is hardness related to strength?
For steels, UTS (MPa) ≈ 3.45 × HB.