How to convert ounce, pound, 1/2, 1/4, 1/8 etc. to gram?

[SyndicateJuggalos17]

if I'm not mistaken, it's really 28.5g in an oz, but u usually get 28. Some of the lists above are scattered so I'll try to help:

1 oz = 28 grams so an eighth is 3.5, a quad is 7, and a half is 14.
1 lb = 16 oz so a QP is 4oz, and a half is 8oz

This is in America.