Grammage are the same weight paper having different cut size. However, a sheet of common copy paper that has a basis weight of does not have the same mass as the same size sheet of coarse paper (newsprint). In the former case, the standard ream is 500 sheets of paper, and in the latter, 500 sheets of paper. Here are some basic ream sizes for various types of paper. Units are inches except where noted. Sheets can be cut into four sheets, a standard for business stationery known conventionally as "letter sized paper". So, the ream became commonly used. The book-paper
Paper size a number of different sizes were defined for large sheets of paper, and paper sizes were defined by the sheet name and the number of times it had been folded. Thus a full sheet of "royal" paper was 25 × 20 inches, and "royal octavo" was this size folded three times, so as to make eight sheets, and was thus 10 × inches. Imperial sizes were used in the United Kingdom and its territories. These sizes are no longer commonly used since the UK switched to ISO sizes. Many of these sizes were only used for making books (see bookbinding),