The second measure is the reduction in area at the fracture. This value is also expressed as a percentage and referred to as the percent reduction of area.

It is calculated as:

$\mathrm{percent} \mathrm{reduction} \mathrm{of} \mathrm{area}=\frac{{\mathrm{A}}_{\mathrm{o}}-{\mathrm{A}}_{\mathrm{f}}}{{\mathrm{A}}_{\mathrm{f}}}(100\%)$

where

${\mathrm{A}}_0=$ original specimen cross-sectional area and

${\mathrm{A}}_{\mathrm{f}}=$ specimen cross-sectional area on the fracture surface.