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March 1, 2011

Proposed Rules Would Allow Metric Only Labeling for Some 

Products

Byline: Mark Esser

The National Institute of Standards and Technology (NIST) has issued two publications calling for the 

amendment of labeling laws to allow the voluntary use of only metric units on some consumer products. 

NIST researchers suggest that adoption of metric labeling will lead to greater agreement between state 

and federal labeling laws and simplify domestic and international commerce.

The Fair Packaging and Labeling Act (FPLA) 

specifies the type of information that must 

appear on a consumer product label, including 

the kind of product, name of the manufacturer 

or responsible party, and net contents. 

Products that aren't covered by the federal law 

are regulated by the states, which generally 

follow the guidance of the Uniform Packaging 

and Labeling Regulations (UPLR), a publication 

(Handbook 130, Uniform Laws and Regulations 

in the areas of Legal Metrology and Engine Fuel 

Quality) produced by NIST and the National 

Conference on Weights and Measures 

(NCWM). The rules in the UPLR are 

recommended regulations that only become 

law if and when adopted by individual states. 

In 1992, NIST and the NCWM supported 

Congress's decision to amend the FPLA to allow 

manufacturers to label their products with U.S. 

customary units (inch/pound/pint, etc.) and metric units (centimeter/kilogram/liter, etc.), known as dual 

unit labeling. Since then, NIST and the NCWM have been working with the states to help them adopt 

laws that would permit metric only labeling of products under their jurisdiction. Forty-eight states have 

adopted this approach.

However, some manufacturers worry that the option to label products solely with metric units will 

confuse consumers and that it will force manufacturers to redesign product packaging.

From left to right, cartons A and B feature a dual net quantity 

of contents statement on the label, as required under the 

current Fair Packaging and Labeling Act (FPLA). Carton C (far 

right) features only a metric label, as is recommended by the 

Uniform Packaging and Labeling Regulation (UPLR), but 

prohibited by the FPLA. A proposed FPLA amendment would 

permit U.S. manufacturers to choose either dual or metric 

labeling for their products.
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To allay these concerns, NIST Metric Program coordinator, Elizabeth Gentry, notes that many products, 

especially wine and distilled spirits, have been sold with metric-only labels since the early 1980s. A 

study by her group found that 193 of 1,137 products surveyed in 19 retail stores were labeled with 

metric units only. More than half of those products were made or distributed by U.S. companies. 

Moreover, she notes that, under the proposal, use of metric only labeling would be voluntary, as would 

package modifications.

Gentry says there is nothing compelling manufacturers to change package sizing simply because they 

have the option to use only metric units on their labels. Manufacturers would be free to continue 

including U.S. customary units in the dual unit labeling scheme. The proposed changes to the FPLA 

would not apply to unit pricing, advertising, recipes, nutrition labeling or other general pricing 

information. 

“We're suggesting these changes to the FPLA in response to requests by U.S. manufacturers and 

consumers,” says Gentry. “Manufacturers want to take control of the limited space on their packaging 

and giving them the option of using only metric units will offer manufacturers more flexibility."

Download NIST’s Guide to Voluntary Metric Labeling

Download NIST’s Labeling Marketplace Assessment

(This article first appeared in the NIST Tech Beat, June 23, 2010)