Walmart, Costco and four other retailers reached an agreement with New York's attorney general to list unit prices on their websites and mobile apps for shoppers nationwide within nine months.
The other retailers were CVS, Walgreens, FreshDirect.com and Drugstore.com. Amazon refused to participate.
According to the attorney general's office, 19 states and the District of Columbia require stores to show unit pricing on consumable items like food, toiletries, over-the-counter medication and pet food. Other states have voluntary guidelines.
Unit pricing helps consumers to quickly compare prices of different items regardless of quantity, manufacturer, packaging size or discounts. The price per ounce (or pound, gram, liter, etc.) is generally displayed next to the retail price.
"As the internet becomes the shopping mall of the 21st century, we need to ensure that consumers have the same robust protections online that they do in brick-and-mortar stores," said Attorney General Eric Schneiderman in a press release.
Some of the six retailers already have unit pricing on some parts of their websites but are further extending the programs.
"Walmart is pleased it could work with the New York attorney general to bring all consumers — in New York and across the U.S. — greater transparency as they shop online," Walmart said in a statement sent to media outlets. "As part of this, Walmart.com is expanding the unit pricing we already offer, in areas like pets and Walmart to Go online grocery, to other categories."
Although Amazon lists unit prices for some items, it doesn't do so consistently, the attorney general's office said. Amazon promised to list unit prices for its subsidiary, which runs Diapers.com, Soap.com, and other shopping sites, but did not commit to it in writing, the office added.
Listing unit pricing began arriving in the seventies. Even in states where it's not required, many stores provide them as a service to customers. Laws and regulations can vary by state, often confusing consumers. Critics say it causes consumers to focus just on quantity rather than quality.
In an update on the effort in 2011, the federal National Institute of Standards and Technology (NIST), which develops standards for unit pricing, pointed to several retailer benefits: improving in-stock conditions; reducing pricing errors; promoting private label products; helping eliminate the need for item pricing; and including stocking and health information.
Do you agree or disagree that unit pricing improves pricing transparency for consumers?