I bought some powdered preservative that was advertised as so many ounces and when it arrived it was obviously not that many ounces by weight. I was told it was by volume when I inquired. I guess my question is how are the dry powdered forms of these products usually sold. When it says ounces should it be by weight?

The ounces indicate the container size, at least with most retail trapper supply businesses, so by volume. Baits and lures same way.

We sell sodium benzoate by weight in a bag form. Some sell by volume in a pint size container. Technically a 16 oz. bait jar is that volume of product. It is sold by both ways.

Our methyl paraben we sell by volume container. 4 oz. etc.

Thanks for the replies. The industry I work in sells dry products by weight, so it surprised me other industries are different. I thought an oz., lb., etc. of dry product had to weigh that amount. Live and learn I guess.

Many of your grocery products are sold by volume and some by weight. There are also liquid volumes and 16 oz. weight containers as well. You can have a 16 oz. volume container that has product that only weighs 8 or 12 oz.