{"id":820,"date":"2013-10-28T14:03:21","date_gmt":"2013-10-28T14:03:21","guid":{"rendered":"http:\/\/www.library.yorku.ca\/web\/?page_id=820"},"modified":"2025-10-20T14:29:54","modified_gmt":"2025-10-20T18:29:54","slug":"understanding-call-numbers","status":"publish","type":"page","link":"https:\/\/www.library.yorku.ca\/web\/research-learn\/academic-research-guides\/understanding-call-numbers\/","title":{"rendered":"Understanding Call Numbers"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">What is a call number?<\/h2>\n\n\n\n<p>Call numbers are like the address of a book. They provide a path to locating a book or other resource in our library collection. At York Libraries, we use the <a href=\"http:\/\/www.loc.gov\/catdir\/cpso\/lcco\/\">Library of Congress classification system<\/a> to make call numbers. You\u2019ll find call numbers both on a book\u2019s spine and on the library website.&nbsp;<\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:100%\">\n<figure class=\"wp-block-table\"><table><tbody><tr><th>Book\u2019s spine<\/th><th>Book\u2019s record on the library website (OMNI)<\/th><\/tr><tr><td><img loading=\"lazy\" decoding=\"async\" width=\"880\" height=\"1416\" class=\"wp-image-32627\" style=\"width: 150px\" src=\"https:\/\/www.library.yorku.ca\/web\/wp-content\/uploads\/2025\/10\/cn.png\" alt=\"\" srcset=\"https:\/\/www.library.yorku.ca\/web\/wp-content\/uploads\/2025\/10\/cn.png 880w, https:\/\/www.library.yorku.ca\/web\/wp-content\/uploads\/2025\/10\/cn-186x300.png 186w, https:\/\/www.library.yorku.ca\/web\/wp-content\/uploads\/2025\/10\/cn-636x1024.png 636w\" sizes=\"auto, (max-width: 880px) 100vw, 880px\" \/><\/td><td><img loading=\"lazy\" decoding=\"async\" width=\"853\" height=\"151\" class=\"wp-image-32638\" style=\"width: 1200px\" src=\"https:\/\/www.library.yorku.ca\/web\/wp-content\/uploads\/2025\/10\/call-number-omni.jpeg\" alt=\"\" srcset=\"https:\/\/www.library.yorku.ca\/web\/wp-content\/uploads\/2025\/10\/call-number-omni.jpeg 853w, https:\/\/www.library.yorku.ca\/web\/wp-content\/uploads\/2025\/10\/call-number-omni-300x53.jpeg 300w\" sizes=\"auto, (max-width: 853px) 100vw, 853px\" \/><\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n<\/div>\n\n\n\n<h2 class=\"wp-block-heading\">How do I read call numbers?<\/h2>\n\n\n\n<p>You read each piece or line of the call number individually. Using the example above (<strong>QC 21.3 H35 2002<\/strong>):<\/p>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-constrained wp-block-group-is-layout-constrained\">\n<figure class=\"wp-block-table\"><table><tbody><tr><td><strong>QC<\/strong><\/td><td>Read this line in alphabetical order: A, B, BF, BK, BP, C ... all the way to Z.&nbsp;<\/td><\/tr><tr><td><strong>21<\/strong><\/td><td>Read this line as a whole number: 1, 2, 3, 100, 101, 1000, 5001, 5980 ... all the way to 9999.<\/td><\/tr><tr><td><strong>.3<\/strong><\/td><td>Read this line as a decimal: .1, .10, .100, .1260, .2, .23, .4, .4590, .6, .600, .9&nbsp;<br>This might feel counter-intuitive, since you\u2019ll have large decimals (.1567) followed by small decimal (.2), but take it one number at a time!&nbsp;<br>Not all call numbers have a decimal, so in that case, skip this step.&nbsp;<\/td><\/tr><tr><td><strong>H35<\/strong><\/td><td>This line is a combination of a letter and number. Read the letter in alphabetical order. Read the number as a decimal.&nbsp;&nbsp;<br>Some examples in correct order: A20, A200, A23, B30, B450, B55&nbsp;<br>Some call numbers might have two of these letter\/number combinations. Follow the same steps to read it.&nbsp;<\/td><\/tr><tr><td><strong>2002<\/strong><\/td><td>This is the publication year, which is important if we have multiple editions of the same book. Read this line in chronological order: 1988, 1995, 2003, 2010, 2025&nbsp;<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div><\/div>\n\n\n\n<h2 class=\"wp-block-heading\">Want more practice?<\/h2>\n\n\n\n<p> Put your knowledge to the test! Try our quiz to put these York Library books in the correct call number order: <\/p>\n\n\n\n<div class=\"wp-block-file\"><a id=\"wp-block-file--media-e521072e-40dd-447d-943f-78da943a456a\" href=\"https:\/\/www.library.yorku.ca\/web\/wp-content\/uploads\/2025\/10\/Markham-Shelf-Reading-Guide.pdf\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Call Number Quiz + Answer Key<\/strong> (downloadable PDF)<\/a><\/div>\n","protected":false},"excerpt":{"rendered":"<p>What is a call number? Call numbers are like the address of a book. They provide a path to locating a book or other resource in our library collection. At York Libraries, we use the Library of Congress classification system to make call numbers. You\u2019ll find call numbers both on a book\u2019s spine and on [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":140,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_uag_custom_page_level_css":"","footnotes":""},"class_list":["post-820","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Understanding Call Numbers - York University Libraries<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.library.yorku.ca\/web\/research-learn\/academic-research-guides\/understanding-call-numbers\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Understanding Call Numbers - York University Libraries\" \/>\n<meta property=\"og:description\" content=\"What is a call number? 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