Calculating Youngs Modulus

Hello all

I wondering anyone could help me with the following:-

When plotting a stress strain curve for a material I believe it is normal practice to express Strain in %.

My question would be that when calculating Youngs modulus is it typical to use Strain in units of %?

I if was to plot my stress strain curve then my equations would be:-

Stress = Force / Area

Strain = (Change in Length / Original Length)*100 (Strain is now in units of %)

If I wanted to calculate Youngs Modulus then my equation would be either:-

Youngs Modulus = (Force/Area) / [(Change in Length / Original Length)*100]

Or

Youngs Modulus = (Force/Area) / (Change in Length / Original Length)

Can anyone help?

Thanks