Comparison of Dewey and Library of Congress subject classification

The Dewey Decimal and Library of Congress library classification systems are the two most common systems in the United States and among the most popular world-wide.^[1] These systems organize resources like books or other media by concept and assign call numbers that are, in part used to shelve and retrieve materials.^[2] The Dewey Decimal Classification (DDC) is used predominantly in public libraries in the United States while the Library of Congress Classification (LCC) is used primarily in academic libraries.

Characteristics

The Dewey Decimal Classification (DDC) was first published by Melvil Dewey in 1876,^[3][4] and included a detailed justification for his use of decimal notation.^[5] DDC decimal notation id can be expanded or reduced as needed by libraries.^[3] It was designed for medium and small sized collections,^[6][7] including those found in public libraries, school libraries, and small academic libraries.^[8][9][10] It consists of ten numeric classes that represent broad fields of study.^[9][8][11] Using numbers, each class is divided into ten divisions or subclasses.^[1][11] During the cataloging process, each item is assigned a three-digit DDC number that represents class, division, and section, followed by a cutter number that identifies the author.^[12] For example, the call number 813.54 M37 includes 800 for the main class of literature, 810 for the division of American literature in English, 813 for American fiction in English, and the cutter M37 for the author.^[12]

The Library of Congress Classification (LCC) was introduced in 1900, based on the collection of the Library of Congress, the largest library in the world.^[3][13] LCC was adopted by other institutions with larger or specialized collections, such as those found in academic libraries and research libraries.^{[14][3][8][10]} In 2019, 81 percent of US academic libraries and 93 percent of Nigeria's academic libraries used the Library of Congress Cataloging system.^[15] LCC has 21 main classes, each designated with a letter of the alphabet, excluding I, O, W, X, and Y which are used to accommodate special needs of libraries that use the classification scheme.^[2][9][16] Its alpha-numeric call numbers include four parts: class/subclass, topic, cutter number, and publication date.^[8][1] For example, HV4708 .R83 2011, where HV stands for social sciences, 4708 is the topic social welfare, .R83 is the cutter number which represents the author, and 2011 is the year of publication.^[8]

Both classification systems are used to create a functional topical order of the resources on the library shelves.^[4] They vary in their notation: DDC is a numeric classification system, while LCC is an alpha-numeric system.^[17][13] LCC was developed specifically for the Library of Congress collection, while DDC was created as a system that could be adapted to a variety of library sizes and specialties.^[13] D. Kent Halsted noted, "Neither scheme is perfect nor will ever be."^[4] As with any classification system, both DDC and LCC include the bias of their creators; in this case, both systems were developed by white, Christian, male academic scholars in late 19th century America.^[18]

There are various factors that determine which classification system a library uses.^[4] The global library cooperative OCLC notes that "A library should base its decision on close versus broad classification on the size of its collection and the needs of its users."^[19] Usually, the size of a library's collection determines whether it selects DDC or LCC.^[9] While DDC was designed for medium-sized libraries,^[6] LCC allows libraries with larger collections to be more specific or precise with classifications.^[9][8][4] Thus, DDC is preferred by institutions with collections under 200,000, while LCC is recommended if the collection includes more than 500,000 items.^[4][20] In the 1960s and early 1970s, many larger academic libraries changed from Dewey Decimal Classification to Library of Congress Classification.^[21][4] After converting the college's library from DCC to LCC in 2021, West Coast Baptist College's director of library services Alyssa Sultanik concluded,

LCC tends to divide resources into smaller subclasses and may be more suitable for larger collections. Several factors can play a part in the success of LCC, such as the practicality of LCC for academic libraries, the ease of use in a specialized collection, and the ability to grow for expanding libraries and the ability to easily add new topics as needed. The collection size, depth of the materials, and intended use of the library collection should be considered when choosing between classification systems...Smaller collections may be more suited for DDC because of the classification's more generalized nature.^[16]

Comparison

The following table compares the organization of resources by the Dewey Decimal and Library of Congress classification systems.^{[11][22][23][24][25][26][27]} It includes all 99 second-level (two-digit) Dewey Decimal classes (excluding 040), and all second-level (two-digit) Library of Congress classes.

Dewey Decimal	Library of Congress	Description	Ref.
000	A, AZ, QA, TA, Z4–659	Computer science, knowledge, and general works; history of scholarship and learning	[28][29][30]
010	AI, Z1001–8999	Bibliography, indexes	[30]
020	Z4–1000.5	Library and information sciences	[30]
030	AE, AG, AY	General encyclopedic works, yearbooks, almanacs, dictionaries, directories	[29]
040		Unassigned
050	AN, AP	General serials and their indexes, periodicals, journals	[29]
060	AM, AS, AY	General organization and museology, academies and learned societies, museums, collectors and collecting, associations, organizations	[29]
070	AN, PN, Z278–549	News media, journalism, publishing, newspapers	[29][31][30]
080	AC	Quotations, collections, collected works, series	[29]
090	Z4-115	Manuscripts, rare books, history of books	[30]
100	B	Psychology and philosophy, philosophy history	[32]
110	B, BD, BH	Philosophy history, metaphysics, speculative philosophy, aesthetics	[32]
120	BD143–237	Epistemology, speculative philosophy	[32]
130	BF1001–1999	Parapsychology, occult sciences, astrology	[32]
140	B, BD	Philosophical schools of thought, speculative philosophy, philosophy history	[32]
150	BF1–940	Psychology	[32][33][28]
160	BC	Logic	[32]
170	BJ	Ethics	[32]
180	B, BL, BQ	Ancient philosophy, medieval philosophy, Eastern philosophy, religions, mythology,rationalism, Buddhism, philosophy history	[32]
190	B	Modern Western philosophy, philosophy history	[32]
200	BL	Religion, mythology	[32]
210	B, BL	Philosophy of religion, theory of religion, philosophy history, religions, mythology	[32]
220	BS	The Bible	[32]
230	BR	Christianity and Christian theology	[32]
240	BR, BT	Christian practice and observance, doctrinal theology	[32]
250	BR, BT	Christian pastoral practice and religious orders	[32]
260	BR, BT	Church organization, social work, worship	[32]
270	BR, BT	Christian church history	[32]
280	BR, BX	Christian denominations, religions	[32]
290	BL, BM, BP, BQ	Other religions, Judaism, Islam, Buddhism, Theosophy, Bahism	[32]
300	H, HM, HN, HQ, HS, HT	Social sciences, sociology, anthropology, human ecology, anthropogeography	[33][34]
310	HA	Statistics	[33]
320	HX, J, JA, JC, JF, JK, JL, JN, JQ, JS, JV, JX	Political science, socialism, communism, anarchism, political theory, theory of the state, Constitutional history, local government, colonies and colonization, emigration and immigration, international law, international relations	[35]
330	HB, HC, HD, HE, HF, HG, HJ	Economics, economics theory, economics history, transportation, communication, commerce, finance, public finance, environmental sciences	[33]
340	JX, K, KD, KE, KF, KG, KH, KJ	Law, international law, law of the United Kingdom, law of Ireland, law of Canada, law of the United States, law of Latin America, law of South America, law of Europe	[36]
350	JF, JS, U, V	Public administration and military science, constitutional history, local government, naval science	[35]
360	HN, HV	Social problems, social services, social history, social reforms, social pathology, criminology	[33]
370	L	Education	[37]
380	HE, HF	Commerce, communications, and transport	[33]
390	BJ, CE, GR, GT	Customs, etiquette, folklore, calendar, manners	[34]
400	P, AG	Language, philology, linguistics, dictionaries	[31]
410	P	Linguistics, philology	[31]
420	PE	English language, Old English languages, English philology	[31]
430	PD, PF	Germanic languages, Germanic philology, West Germanic language, West Germanic philology	[31]
440	PC	French language, Romance philology	[31]
450	PC	Italian language, Romanian language, Rhaeto–Romanic language, Romance philology, Romance languages	[31]
460	PC	Spanish language, Portuguese language	[31]
470	PA, PC	Latin language, Italic languages, classical philology, classical literature; modern Greek literature, Byzantine literature, medieval Latin literature, modern Latin literature, Romance philology	[31]
480	PA	Classical Greek language, modern Greek language, classical philology, classical literature, Byzantine literature, modern Greek literature, medieval Latin literature, modern Latin literature	[31]
490	PB, PG, PH, PJ, PK, PL, PM	Other Languages: Celtic language, Celtic literature, Slavic languages, Slavic literature, Baltic languages and literature, Albanian language, Albanian literature, Finno-Ugarian languages and literature, Basque language, Basque literature, Egyptian language and philogy, Coptic language and philogy, Hamitic language and philogy, Semitic languages,Semitic philology, Indo-Iranian languages, Indo-Iranian literature, Eastern Asian languages, Eastern Asian literature, Oceanian languages, Oceanian literature, African languages,African literatures, American Indian languages, artificial languages	[31]
500	Q	Science	[28]
510	QA	Mathematics, computer science	[28]
520	QB	Astronomy	[28]
530	QC	Physics	[28]
540	QD	Chemistry, crystallography	[28]
550	QE, GC	Earth sciences, geology, oceanography	[28][34]
560	GF, GN, QE, QH	Fossils, prehistoric life, human ecology, anthropogeography, anthropology, geology, natural history, biology	[28]
570	QH, QP, QR	Life sciences, biology, natural history, microbiology	[28][34]
580	QK	Botany	[28]
590	QL	Animals, zoology	[28]
600	T	Technology (applied sciences)	[38]
610	QM, R, RA, RB, RC, RD, RE, RF, RG, RJ, RK, RL, RM, RS, RT, RV, RX, RZ	Medicine, human anatomy, public health, pathology, internal medicine, surgery, ophthalmology, otorhinolaryngology, gynecology, obstetrics, pediatrics, dentistry, dermatology, therapeutics, pharmacology, pharmacy, nursing, Thomsonian medicine, eclectic medicine, homeopathy, other systems of medicine	[39][28]
620	TA, TC, TD, TE, TF, TG, TJ, TK, TL, TN, TR	Engineering, hydraulic engineering, environmental engineering, sanitary engineering, highway engineering, roads and pavement, railroads, railway engineering, mechanical engineering, electrical engineering, nuclear engineering, motor vehicles, aeronautics, astronautics, mining engineering, metallurgy, photography	[38][28][40][41]
630	S, SB, SD, SF, SH, SK	Agriculture, plant industry, animal industry, plant culture, forestry, animal culture, aquaculture, fisheries, angling, hunting	[42]
640	TT, TX	Home management, family management, home economics, handicrafts, arts and crafts	[38]
650	H, HA, HB, HC, HD, HF, HG, HM	Management, public relations, social sciences, statistics, economic theory, demography, economic history, commerce, finance, public finance	[33]
660	TP	Chemical engineering	[38]
670	TS	Manufacturing	[33]
680	TS, TT	Manufacturing specific products, graphic arts	[38]
690	TH	Building and construction	[38]
700	N, NX	Arts, visual arts	[43]
710	SB	Landscaping, area planning, plant culture	[42]
720	NA	Architecture	[43]
730	NB, CJ	Sculpture, ceramics, metalwork, numismatics	[43]
740	NC, NK	Drawing, decorative arts, design, illustration, applied arts, decoration, ornament	[43]
750	ND	Painting, drawing, design, illustration, painting, print media	[43]
760	NC, ND, NE	Graphic arts, printmaking, prints	[43]
770	TR	Photography and photographs	[38]
780	M, ML, MT	Music, instrumental music, vocal music, literature of music, music instruction	[44]
790	GV	Sports, games, entertainment, recreation, leisure	[31][34]
800	P, PN	Literature, rhetoric, criticism, language, literary history, literary collections, theater, oratory, journalism	[31]
810	PS, PZ	American literature in English, juvenile belles letters	[31]
820	PR, PZ	English literature, Old English literature, juvenile belles letters	[31]
830	PT, PZ	German literature, Germanic literature, juvenile belles letters	[31]
840	PQ, PZ	French literature, Romance literature, juvenile belles letters	[31]
850	PQ, PZ	Italian literature, Romanian literature, Romance literature, juvenile belles letters	[31]
860	PQ, PZ	Spanish literature, Portuguese literature, Romance literature, juvenile belles letters	[31]
870	PQ, PZ	Latin literature, Italian literature, Classical philology, Classical literature, Byzantine literature, medieval Latin literature, modern Latin literature, juvenile belles letters	[31]
880	PA, PZ	Classical Greek literature, modern Greek literature, classical philology and literature, juvenile belles letters	[31]
890	PB, PG, PH, PJ, PK, PL, PZ	Other languages, Celtic languages, Celtic literature, Slavic languages, Slavic literature, Baltic languages and literature, Albanian languages, Albanian literature, Finno-Ugarian languages and literature, Basque language, Basque literature, Egyptian language and philology, Coptic language and philology, Hamitic languages and philology, Semitic languages, Semitic philology, Indo-Iranian languages, Indo-Iranian literature, Eastern Asian languages, East Asinan literature, Oceanic languages, Oceanian literature, African languages, African literature, juvenile belles letters	[31]
900	CB, D, E, F	History, history of civilization, topography, history of the United States, local history of the United States, history of North America except the U.S., history of South America	[34][45][46]
910	G, GA, GB	Geography, travel, mathematical geography, cartography, physical geography	[34][46]
920	CD, CR, CS, CT	Biography, genealogy, diplomatics, archives, seals, heraldry	[46]
930	CB, CC, CN, DA, DAW, DB, DC, DD, DE, DF, DG	History of ancient world (to ca. 499 A.D.), history of civilization, archaeology, epigraphy, inscriptions, classical antiquity, Great Britain, Central Europe, Austria, Lichtenstein, Hungary, Czechoslovakia, France, Andorra, Monaco, Germany, East Germany, Mediterranean, Greece, Italy, Malta	[45]
940	DA, DAW, DB, DC, DD, DF, DG, DH, DJ, DJK, DK, DL, DP, DQ, DR	History of Europe (ca 500 A.D.), Great Britain, Central Europe, Austria, Liechtenstein, Hungary, Czechoslovakia, France, Andorra, Monaco, Germany, East Germany, Greece, Italy, Malta, Belgium, Luxembourg, Holland, Eastern Europe, Soviet Union, Poland, Scandinavia, Spain, Portugal, Switzerland, Balkan peninsula	[45]
950	DS	History of Asia, China, Japan, Arabian Peninsula, Saudi Arabia, India, Iran (Persia)	[45]
960	DT	History of Africa, Libya, Tunisia, Egypt, Sudan, Ethiopia (Abyssinia), Eritrea, Algeria, West Africa, Central Africa, South Africa	[45]
970	E, F1–1392	History of North America, United States, Canada, Mexico	[47]
980	F1401–3799	History of South America, Central America, Brazil, Argentina, Chile, Bolivia, Peru, Venezuela	[47]
990	DU	History of other regions, Oceania, Australia, New Zealand, Melanesia, New Guinea	[45]

See also

• Classification
• Decimal classification
• Library catalog
• Library of Congress Subject Headings
• List of Dewey Decimal classes

Further reading

• Billy, Amber; Nelson, Elizabeth; and Uhl, Rebecca. Inclusive Cataloging: Histories, Context, and Reparative Approaches. Chicago: ALA Editions, 2024. ISBN 979-8-89255-566-1.
• Chan, Lois Mai. A Guide to the Library of Congress Classification, 6th ed. New York: Libraries Unlimited, 2016. ISBN 978-1440844331.
• Chan, Lois Mai and Salaba, Athena. Cataloging and Classification: An Introduction. Lanham, Maryland: Rowman & Littlefield Publishers, Inc., 2016. ISBN 9781442232495.
• Merkley, Carl. "The Library of Congress, Dewey Decimal, and Universal Decimal Classification Systems are Incomplete and Unsystematic". Evidence Based Library and Information Practice, vol. 6, no. 4 (2011): 134–136. doi.org/10.18438/B8QK7S.
• Satija, M. P. The Theory and Practice of the Dewey Decimal Classification System. Hull: Chandos Publishing, 2013. ISBN 978-1843347385.
• Scott, Mona L. Dewey Decimal Classification: A Study Manual and Number Building Guide, 22nd edition. New York: Libraries Unlimited, 2005. ISBN 978-1591582106.
• Sroka, Marek. "Library of Congress Subject Headings, Dewey Decimal Classification and the Ambiguity of Subject Representation of Central, Eastern and South-Eastern Europe in American Knowledge Organization Systems." Central European and Balkan Studies, vol. 33 (November 21, 2024): 9–16. doi.org/10.4467/2543733XssB.24.001.20025
• Weihs, Jean and Intner, Sheila S. Beginning Cataloging, 2nd edition. Bloomsbury Publishing, 2016. ISBN 9798216052197.

References

1. "Cataloging Tools and Resources: Classification". American Library Association. Retrieved 2025-08-21.
2. Francis, Frank C.; Estabrook, Leigh S. (2025-08-09). "The Dewey Decimal system". Britannica. Retrieved 2025-09-01.
3. "LibGuides: Cataloging Tools and Resources: Classification". American Library Association. Retrieved 2025-08-28.
4. Halstead, D. Kent. "Chapter IX: College and University Libraries: Bibliographic Access" in Statewide Planning in Higher Education (DHEW Publication No. 73-17002). Washington, D.C.: U.S. Government Printing Office, 1974. p. 400-408.
5. Comaromi, John P. (1976), The eighteen editions of the Dewey Decimal Classification, Albany, N.Y: Forest Press Division, Lake Placid Education Foundation, p. 43, ISBN 978-0-910608-17-6, OL 4881898M
6. Hjørland, Birger (2025). "Dewey Decimal Classification (DDC)". Em Questão. 31. doi:10.1590/1808-5245.31.145068. ISSN 1808-5245.
7. Universal Decimal Classification (UDC) was created in 1905 based on DDC 5th edition to address the needs of large libraries.
8. Moeller, Kimberly (2023-10-31). "Peer Navigator Corner: Library of Congress vs. Dewey Decimal System". Library News. University of Missouri Libraries. Retrieved 2025-08-21.
9. "Comparing LC and Dewey". University of Mississippi Library. Retrieved 2025-08-21.
10. "Call Numbers and the Library of Congress Classification System | HCC". Henderson Community College. Archived from the original on 2025-05-22. Retrieved 2025-08-28.
11. Summaries DDC: Dewey Decimal Classification (PDF). Dublin, Ohio: OCLC Online Computer Library Center, Inc. 2003. ISBN 0-910608-71-7. Retrieved August 28, 2025.
12. "Basic Cataloging: Intro to Call Numbers". Internet Public Library. Retrieved 2025-08-22.
13. Bullard, Eric. "Library of Congress Classification (LCC) | Research Starters". EBSCO. Retrieved 2025-09-01.
14. Lavallee, Andrew (July 20, 2007). "Discord Over Dewey: A New Library in Arizona Fans a Heated Debate Over What Some Call the 'Googlization' of Libraries". Wall Street Journal. Retrieved May 25, 2013.
15. Lund, Brady; Agbaji, Daniel; Tijani, Solomon; Omame, Isaiah (2019-07-03). "Evaluating Knowledge Organization in Developed and Developing Countries: A Comparative Analysis of Dewey Decimal and Library of Congress Classification Scheme Preference and use in the United States and Nigeria". Technical Services Quarterly. 36 (3): 249–268. doi:10.1080/07317131.2019.1621563. ISSN 0731-7131.
16. Sultanik, Alyssa (April 7, 2022). "Lessons learned about converting from Dewey Decimal Classification to Library of Congress Classification". The Christian Librarian. 65 (1).
17. List-Handley, Carla J. (2002). Information Research. Kendall Hunt. p. 5. ISBN 978-0-7872-9057-3 – via Google Books.
18. Christiansen, Andrew (2022-04-14). "SLCC switches library classifications". The Globe. Retrieved 2025-09-03. Jon Glenn, director of library services, said we … wanted to make our system more equitable and inclusive, which isn't really a question of which system was originally more biased, but rather which system...can be more easily improved upon...Any classification system is rooted in and biased by its creator and the time under which it was created. Glenn added that this applies to DDC and LCC, which were both developed in the United States during the 19th century by academic scholars who were white, male, and Christian.
19. "Introduction to the Dewey Decimal Classification" (PDF). OCLC. May 17, 2019. p. 37. Retrieved September 2, 2025.
20. As Halstead notes, there are exceptions, with smaller institutions using LCC and larger institutions still using DDC.
21. Shorten, Jay Shorten; Seikel, Michele; Ahrberg, Janet H. (April 2005). "Why Do You Still Use Dewey? Academic Libraries that Continue with Dewey Decimal Classification". Library Resources & Technical Services. 49 (2). American Library Association. Retrieved September 1, 2025 – via Gale Academic OneFile.
22. Scott, Mona L. and Alvey, Christine E. Conversion Tables: LC-Dewey, Dewey-LC. 17th edition. Englewood: Libraries Unlimited, 1993. ISBN 9781563080173
23. "Map Dewey (DDC) to LC (LCC) Classification". Questionpoint.org. OCLC. Archived from the original on 2018-05-03. Retrieved 2025-08-21.
24. "Map LC (LCC) to Dewey (DDC) Classification". Questionpoint.org. OCLC. Archived from the original on 2018-04-19. Retrieved 2025-08-21.
25. "Library of Congress Classification Outline". The Library of Congress. Retrieved 2025-08-21.
26. "Dewey Decimal System – A Guide to Call Numbers". Information Sciences Virtual Library. University of Illinois Library. Retrieved 2025-08-22.
27. "Dewey Decimal vs. Library of Congress". Randolph C. Watson Library. Kilgore College. Archived from the original on 2024-03-15. Retrieved 2025-09-01.
28. "Library of Congress Classification Outline – Class Q" (PDF). Library of Congress. Retrieved August 21, 2025.
29. "Library of Congress Classification Outline – Class A" (PDF). Library of Congress. Retrieved August 21, 2025.
30. "Library of Congress Classification Outline – Class Z" (PDF). Library of Congress. Retrieved August 21, 2025.
31. "Library of Congress Classification Outline – Class P" (PDF). Library of Congress. Retrieved August 21, 2025.
32. "Library of Congress Classification Outline – Class B" (PDF). Library of Congress. Retrieved August 21, 2025.
33. "Library of Congress Classification Outline – Class H" (PDF). Library of Congress. Retrieved August 21, 2025.
34. "Library of Congress Classification Outline – Class G" (PDF). Library of Congress. Retrieved August 21, 2025.
35. "Library of Congress Classification Outline – Class J" (PDF). Library of Congress. Retrieved August 21, 2025.
36. "Library of Congress Classification Outline – Class K" (PDF). Library of Congress. Retrieved August 21, 2025.
37. "Library of Congress Classification Outline – Class L" (PDF). Library of Congress. Retrieved August 21, 2025.
38. "Library of Congress Classification Outline – Class T" (PDF). Library of Congress. Retrieved August 21, 2025.
39. "Library of Congress Classification Outline – Class R" (PDF). Library of Congress. Retrieved August 21, 2025.
40. "Library of Congress Classification Outline – Class U" (PDF). Library of Congress. Retrieved August 21, 2025.
41. "Library of Congress Classification Outline – Class V" (PDF). Library of Congress. Retrieved August 21, 2025.
42. "Library of Congress Classification Outline – Class S" (PDF). Library of Congress. Retrieved August 21, 2025.
43. "Library of Congress Classification Outline – Class N" (PDF). Library of Congress. Retrieved August 21, 2025.
44. "Library of Congress Classification Outline – Class M" (PDF). Library of Congress. Retrieved August 21, 2025.
45. "Library of Congress Classification Outline – Class D" (PDF). Library of Congress. Retrieved August 21, 2025.
46. "Library of Congress Classification Outline – Class C" (PDF). Library of Congress. Retrieved August 21, 2025.
47. "Library of Congress Classification Outline – Classes E and F" (PDF). Library of Congress. Retrieved August 21, 2025.

External links

• Quick Start Tutorial: LC/Dewey Correlations (Library of Congress).
• Ross, Geoffrey. Dewey → Library of Congress Classification (History, Philosophy, and Newspaper Library, University of Illinois).