Imperial/Metric conversion question

[sutepan]

I have a conversion program that gives me two different imperial measurements for mass; troy or avdp. Which should I use when converting recipes to metric? For example, when converting hops, should I convert from troy ounces or avdp ounces to grams?

 

[BigEd]

Avoirdupois is the common measurement of weight/mass for ounces & pounds.

 

[sutepan]

Thanks!