Fig. 1 shows the Lateral Expansion and Impact Energy for specimens with dimensions of 10mm X 10mm.

For impact energies measuring about 100 J, the resulting expansion can be calculated by:
Charpy Energy (J)/100 = LE(mm)

This is non-applicable for impact energies that are beyond 100 Joules, or higher energies. Some ferritic steels experience a reduction of lateral expansion at greater measures of Charpy energy levels.