Paper size impossible to encounter ISO standard papers in day-to-day uses, with "Carta" (Letter), "Oficio" (Government-Legal) and "Doble carta" (Ledger/Tabloid) being nearly universal. In Canada, US paper sizes are a de facto standard. The government, however, also uses ISO paper sizes. There is an additional paper size, , to which the name "Government-Letter" was given by the IEEE Printer Working Group (PWG). It was prescribed by Herbert Hoover when he was Secretary of Commerce to be used for US government forms, apparently to enable discounts from the purchase of paper for schools, but more likely due to the standard use of trimming
Paper size below. "Letter, Legal" and "Ledger/Tabloid" are by far the most commonly used of these for everyday activities, and the only ones included in Cascading Style Sheets (CSS). The origins of the exact dimensions of Letter size paper () are lost in tradition and not well documented. The American Forest and Paper Association argues that the dimension originates from the days of manual paper making, and that the 11-inch length of the page is about a quarter of "the average maximum stretch of an experienced vatman's arms." However, this does not explain the width or aspect ratio. Outside of North America,