The slide rule, invented by William Oughtred in 1622, consists of two divided scales, one fixed and one movable, and a sliding window called a cursor. Slide rules were the primary tool for performing multiplication, division and other scientific functions up through the 1960s and the development of the electronic calculator.

There are straight, circular and cylindrical slide rules, all collectible. Major manufacturers included Keuffel and Esser, Pickett, Gilson, Dietzgen, Post (which became Teledyne), Faber-Castell, Aristo, and others. Early slide rules were made of wood and celluloid, while later ones tended to be plastic or metal.

The rarest slide rules are 19th Century hand-engraved instruments such as Palmers Computing Scale (a circular model), first published in 1843, or the cylindrical ‘Thacher’s Patent Calculating Instrument’ slide rules produced by Keuffel and Esser Co in the 1880s. These can run close to $1,000 in good condition.

Whatever you do, be sure any slide rule you buy is fully intact and working, as finding replacement parts for a specific model (especially the cursor) can be next to impossible.


Best of the Web (“Hall of Fame”)

Slide Rule Museum

Slide Rule Museum

Mike Konshak's amazing antique slide rule reference site 'dedicated to students and engineers of the past and prese… [read review or visit site]

Early Office Museum

Early Office Museum

This site showcases pre-1920 office antiques, including paperweights, writing ink, paper fasteners, seal pressers, … [read review or visit site]



Clubs & Associations

Discussion Forums

Most watched eBay auctions    

Keuffel & Esser K&e Deci-lon 5 Slide RuleSlide Rule For Einstein's Theory Of Relativity From 1957Pickett Circular Slide Rule 103esPost 1461 Pocket Slide Rule Bamboo Laminate By Hemmi JapanPickett Speed Slide Rule Model N600-es Log Log Rule 6 Inches Leather CasePost Hemmi Model 1461 Slide Rule Pickett N4-es Slide Rule, Ex Cond, W CaseVintage K & E 4160 Chemist Duplex Slide Rule With CaseKeuffel & Esser 7l Slide Rule Replacement Glasses ~ Box Of 6K&e Keuffel & Esser Deci-lon 68-1100 Slide Rule Leather CaseVintage Slide Rule Magnifier K E El Keuffel Esser Engineering Nos Usa IndicatorVintage Faber Castell Slide Rule 2/83n Novo Duplex W Case GermanyLumber Calculator Slide Rule, 4inch Weber Plus 2 MorePickett N3-t Slide Rule In Box New Like With Manual!Large Keuffel & Essar 22 1/4'' Slide Rule ( 4083-5 ) - Lqqk -Vintage Pickett & Eckel Slide Rule / Log Rule No N600-es In Leather CaseK & E Deci-lon 10 Slide Rule Keuffel & Esser Vintage 1947-1961 W / Leather CaseUnknown Keuffel & Esser Co. K & E Log Log Mahogany/celluloid 12" Slide Rule Vintage Occupied Japan Sun Hemmi Slide Rule 1462h W/ Leather Case Engineer Vintage Binary Circular Slide Rule 1931 & 1940Pickett N500/300 Paired Set Slide Rule Unused W/box, Cases & ManualVintage Pickett Power Log Exponential Slide Rule W Case Model N 3-esStandardgraph N° 910 Disco Rietz Dbgm Circular Slide Rule W/ Leather Case.Vintage Pickett N 3-es Power Log Exponential Slide Rule With Leather CaseVintage Pickett Model 700 Pocket Slide Rule With Leather CaseVtg Pickett Metal Model N4-t Vector Type Log Dual Base Speed Slide Rule AntiquePickett N-400 Slide Rule 6" In Box W/leather Case And InstructionsVintage Keuffel Esser Slide Rule W/ Leather Case Engineer N4081-3 White RulerVintage Sun Hemmi No. 153 Engineers Slide Rule Made In Japan Good ConditionM. H. Mear & Co., Mear’s Water Flow Calculator No. 3 Slide RuleVintage Post 1460 Versalog Slide Rule Hemmi Japan Belonged To Brigadier GeneralK & E Slide Rule Keuffel & Esser Manual Book 1943, 1945, 1947, 1955 Vtg HardbackVintage Pickett Trig Slide Rule Clear W/ Leather Case Engineer Ruler TransparentVintage Pickett 510-t Business And Finance Slide Rule With Case Vintage Keuffel & Esser K&e Slide RuleKeuffel & Esser Model 4181-1 Pocket Slide Rule With Leather CaseVintage Pickett 109es Circular Slide Rule With Case & InstructionsKeuffel & Esser Deci-lon 10 Slide RuleVintage Japan Sun Hemmi Slide Rule 1446 W/ Black Case Engineer RulerK+e Keuffel & Esser 4081-3 Log Log Duplex Decitrig Slide Rule-1947-case-manualDeci Log Slide Rule Model No. 4 And Keuffel Esser Co Ny & Bruning CoVintage Dietzgen Slide Rule 1759 BDietzgen No1738 Slide Rule Vtg 1950s Drafting Engineering Case & Manual Inc.Vintage Pickett Model 1010-t Slide Rule W/ Leather Case, Box And Instructions Vintage Pickett Slide Rule, Model 4t, W/ Saddle Leather CaseVintage Pickett Slide Rule Model 300 With Leather Case, Box And Instructions6" Uto 601 Slide Rule New In Carrying Case And Box Pennwalt Engineering Vintage A. Lietz - Alco - Mannheim Slide Rule Manual, 1928Keuffel & Esser Co. Cooke Radio Slide Rule 4139Vintage Pickett & Eckel 6" Slide Rule Model 200 With Leather Pickett Case Usa Vintage Keuffel Esser K&e 4080-3s Log Duplex Trig Slide Rule W/original CaseMib 1953 Picket Log Log Model 500-t 10 Inch Slide Rule W Case And Booket1908 Keuffel & Esser Co. Polyphase Duplex Slide Rule # 4088-3 Original CaseVintage Keuffel & Esser 4092-3 Log Log Duplex Slide Rule Original Leather PouchVintage Trigonometry Triangulator Angle Finder Slide Rule Chart Trical CompanyK & E N4058w Slide Rule In Case With InstructionsVintage Slide Rule Lot- Globemaster-japan And Hidraulic Service Center Rules Vintage K & E Keuffel & Esser Co. Beginner's Slide Rule N4058cSlide Rule SimplifiedVintage Pickett Eckel Slide Rule Yellow W/ Leather Case Engineer Ruler 800-es