Vickers Hardness Number Calculator (HV)
Enter the applied load (kgf) and the mean diagonal of the square pyramid indentation (mm) to compute the Vickers Hardness Number HV, and see the result on a material hardness scale from very soft metals to ultra-hard coatings.
kgf
mm
HV = 1.8544 × F / d² (kgf/mm²)
- 1
Diagonal squared (d²)
0.3² = 0.3 × 0.3 = 0.09 - 2
Numerator: 1.8544 × F
1.8544 × 10 = 18.5441.8544 = 2 × sin(68°) from the 136° pyramid geometry. - 3
Vickers Hardness HV
18.544 ÷ 0.09 = 206
How does this calculator work?
Vickers Hardness HV = 1.8544 × F / d², where F is the applied force in kgf and d is the average diagonal of the indentation in mm. The constant 1.8544 = 2 sin(68°) comes from the 136° pyramid geometry. Multiply HV by 9.807 to convert to MPa.
Formula
How this is calculated
In a Vickers hardness test a square-based diamond pyramid with a 136° face angle is pressed into the material surface under a fixed load F (in kgf) for a set dwell time (typically 10–15 seconds). After removing the load, the diagonals of the square impression left in the material are measured under a microscope and averaged to give d (mm). The Vickers Hardness Number is then HV = 1.8544 × F / d², where the constant 1.8544 = 2 sin(68°) arises from the pyramid geometry (136°/2 = 68°).
HV has units of kgf/mm², equivalent to 9.807 MPa. To convert to SI: multiply HV by 9.807 to get MPa, or by 0.009807 to get GPa. For carbon and alloy steels in the range HV 80–400 an empirical approximation gives Brinell hardness HBW ≈ 0.95 × HV, but this relationship is not precise outside that range and should not replace a direct Brinell test.
The test is versatile across load ranges: macro-hardness uses loads of 5–100 kgf (HV5–HV100), micro-hardness uses 0.01–1 kgf (HV0.01–HV1) for thin coatings or small microstructural features. The scale runs from near zero (extremely soft lead or indium) through mild steel (~200 HV) and hardened tool steel (~700 HV) up to 10 000 HV for diamond.
Frequently asked questions
HV is the load divided by the surface area of the pyramid-shaped indentation, expressed in kgf/mm². Higher HV means a harder material that resists plastic deformation. The Vickers scale is continuous and applicable from very soft metals (HV < 10) to near-diamond ceramics (HV > 3 000), unlike Rockwell scales which have load-range limitations.
The Vickers indenter is a square pyramid with a 136° included face angle (68° from the vertical axis on each side). The surface area of the indentation equals d² / (2 sin 68°) = d² / 1.8544, so HV = F / area = 1.8544 F / d². The factor 1.8544 = 2 sin(68°) is exact from the pyramid geometry.
For steels in HV 80–400: HBW (Brinell) ≈ 0.95 × HV. Rockwell conversions depend on the Rockwell scale (C, B, A) and the material, and should use the ISO 18265 or ASTM E140 conversion tables rather than a simple formula, as they are empirical and material-dependent.
Also known as
TG we-Calculate Editorial Team. (2026). Vickers Hardness Number Calculator (HV) [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/vickers-hardness-number-calculator
TG we-Calculate Editorial Team. "Vickers Hardness Number Calculator (HV)." TG we-Calculate. 2026. https://we-calculate.com/calculator/vickers-hardness-number-calculator.
TG we-Calculate Editorial Team, "Vickers Hardness Number Calculator (HV)," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/vickers-hardness-number-calculator
@misc{wecalculate_vickers_hardness_number_calculator, title = {Vickers Hardness Number Calculator (HV)}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/vickers-hardness-number-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?