The standards recommend unit price tags have a font size of 5mm, the unit price should not be less than 50% of the height of the selling price and there should be sufficient contrast between the print and background.
Among those surveyed by Which?, 88% said unit pricing helps them to work out which products and promotions are the best value for money.
Of those who were aware of unit pricing but did not use it, 22% said it was because unit pricing was too small and hard to read.
More top news
New research calls into question certain common, private treatments whose costs can run into the thousands.
1,209 people were found guilty of 'trolling' offences in 2014 - and 155 have been jailed.
Critics are ambivalent to this year's slate of winners, who were picked in part by American directors Joel and Ethan Coen.