Net weight

The first exclusion

On this page11

The definition of weight So weight means net weight by default And net weight is defined by exclusion With a list Containers is first The list is not closed There is one carve-out and it is about services Which does not reach a refill counter Why this is easy to get wrong The fix is arithmetic, and the next page is about it References

Containers, conveyances, bags, wrappers. In that order.

The definition of weight

"The term 'weight' as used in connection with any commodity or service means net weight. When a commodity is sold by drained weight, the term means net drained weight."

So weight means net weight by default

Not as a special case for packaged goods. Any time a commodity is sold by weight, the word already means net.

And net weight is defined by exclusion

"The weight of a commodity excluding any materials, substances, or items not considered to be part of the commodity."

With a list

"Containers, conveyances, bags, wrappers, packaging materials, labels, individual piece coverings, decorative accompaniments, and coupons."

Containers is first

Which is not an accident of alphabetical order, and it is the sentence this entire property exists for. In a refill shop the container is on the scale, and the law has already said it is not part of what is being sold.

The list is not closed

"Include, but are not limited to." A lid, a gasket, a pump, a label the customer stuck on themselves: all of it is the customer's and none of it is the commodity.

There is one carve-out and it is about services

"Except that, depending on the type of service rendered, packaging materials may be considered to be part of the service." The example in the handbook is shipping, where the weight of packing material is part of what is being paid for.

Which does not reach a refill counter

You are selling a commodity, not a shipping service. The packaging is the customer's own and they brought it with them.

Why this is easy to get wrong

Because the obvious way to run the counter is to put the jar on the scale and fill it until the number looks right. That number includes the jar, and the customer paid for it.

The fix is arithmetic, and the next page is about it

Weigh the empty container, record it, subtract it. The whole of compliance here is one subtraction done consistently.

References

NIST Handbook 130, 2023, Uniform Weights and Measures Law. Section 1.2: "The term 'weight' as used in connection with any commodity or service means net weight. When a commodity is sold by drained weight, the term means net drained weight." Section 1.8 defines net mass or net weight as "the weight of a commodity excluding any materials, substances, or items not considered to be part of the commodity. Materials, substances, or items not considered to be part of the commodity include, but are not limited to, containers, conveyances, bags, wrappers, packaging materials, labels, individual piece coverings, decorative accompaniments, and coupons, except that, depending on the type of service rendered, packaging materials may be considered to be part of the service." nist.gov

Written from NIST Handbook 130, 2023 edition, and from the catalog as it stood on 19 October 2026. Handbook 130 is a compilation of model laws rather than federal law, and states adopt it in different forms, from different years, or not at all; the binding text is your state's. Nothing here concerns whether a scale is legal for trade, which is Handbook 44 and a state device approval, or the retail food rules for refilling a customer's food container, which belong to whoever licenses the shop.