Letter (paper size) "official" "Government Letter" size, , was used in government, while paper was standard in most other offices. In the U.S., paper density is usually measured in "pounds per ream" (of 500 sheets). Typical Letter paper has a basis weight of paper of – the weight of 500 sheets (a ream) of paper at and at 50% humidity. One ream of 20-pound Letter-sized paper weighs , and a single Letter-sized sheet of 20-pound paper weighs , which is equivalent to 75.19 g/m. Some metric information is typically included on American ream packaging. For example, 20-pound paper is also labeled as 75
Ruled paper lighter lines 2 mm (appx. 5/64 in) apart between each pair of heavy lines. Heavy vertical lines are spaced 8 mm (appx. 5/16 in) apart, beginning 16 mm (appx. 5/8 in) from the left-hand edge of the page. These sheets of paper are generally known as "grands carreaux" (large tiles) as opposed to the "petits carreaux" (small tiles) which are 5x5mm. Seyès ruled paper is available in single sheets ("copies simples") or joined double sheets ("copies doubles") which are sometimes preferred for exams, being easier to handle. DIN 16552:1977-04 (“Lines for handwriting”) specifies the types of ruled paper to be