Calculator for Conversion between
Vickers Hardness Number and SI Units MPa and GPa

There is now a trend towards reporting Vickers hardness in SI units
(MPa or GPa) particularly in academic papers. Unfortunately, this can
cause confusion. Vickers hardness (e.g. HV/30) value should normally be
expressed as a number only (without the units kgf/mm^{2}).
Rigorous application of SI is a problem. Most Vickers hardness testing
machines use forces of 1, 2, 5, 10, 30, 50 and 100 kgf and tables for
calculating HV. SI would involve reporting force in newtons (compare
700 HV/30 to HV/294 N = 6.87 GPa) which is practically meaningless and
messy to engineers and technicians. To convert a Vickers hardness
number the force applied needs converting from kgf to newtons and the
area needs converting from mm^{2} to m^{2} to give
results in pascals using the formula below.

HV = Vickers hardness

To convert HV to MPa multiply by 9.807
To convert HV to GPa multiply by 0.009807

To use the conversion calculator simply enter a number value into the
desired field and click calculate. All results shown will be equivalent
values. Values are given to four significant figures (the odd result
may show 9's or 0's over running). Values of 10 000 or greater will be
displayed in the e-format e.g. 2.3456e7 which equals 2.3456 x 10^{7}
or 23 456 000. Values lower than 0.001 will be displayed in the
e-format e.g. 2.3456e-5 which equals 2.3456 x 10^{-5} or 0.000
023456. The calculators require that your browser has java script
enabled.