# Vickers hardness number for a giving area

## Description

The hardness number is determined by the load over the surface area of the indentation and not the area normal to the force, and is therefore not pressure.

The corresponding units of HV are kilograms-force per square millimeter (kgf/mm²). To convert the Vickers hardness number to SI units the hardness number in kilograms-force per square millimeter (kgf/mm²) has to be multiplied with the standard gravity (9.806 65) to get the hardness in MPa (N/mm²) and furthermore divided by 1000 to get the hardness in GPa.

Related formulas## Variables

HV | hardness number (kgf/mm^{2}) |

F | force applied to the diamond (kgf) |

A | intendation area (mm^{2}) |