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    

Breitling Chronospace With Boxes, Manuals And Slide Rule Vintage, Professor Fuller, Stanley Tool, Calculating Slide Rule Computer & Case,Vintage Slide Rule: Pocket Pickett N 4p-t Vectr Type Log Log Dual Base Speed Vintage Slide Rule: Fowler's Long Scale Calculator Double Sided, In Case C.1898Vintage Frederick Post Versalog Slide Rule #1461 W/caseAristo Nuclear Slide Rule 10174. Near Mint! Very Rare! Echoes Of Cold War.Unusual Vintage Wooden Slide Rule Calculating Alcohol Customs Excise Dring FageVintage Pickett Slide Rule Model 6-t Statistical Quality Control With Case 12inAristo Studiolog 0969 Slide RulePickett / Lietz Circular Slide Rule 101-c W/case & Manual Excellent ConditionIncredible Picket 7 Foot Vintage Slide Rule! Classroom Or Advertisement Size!Pickett, Post, K&e, Hemmi, Dietzgen Slide Rule Lot!!Pickett Slide Rule N4-es Log Vintage 1959 With Leather Case Pickett Eckel UsaFaber-castell German Slide Rule4.75 " Dia Fowler Magnum Long Scale Slide Rule With Re-mfg Front GlassVintage Round Slide Rule Russia 1950 Vtg. Dietzgen Midget Circular Slide Rule Excellent W/ Manual Instructions CaseKeuffle & Esser 4105 Webb's Stadia Cylindrical Slide RuleSun Hemmi 5inch Pocket Slide Rule, CaseVtg Secret Code-maker Slide Rule, Box; 1939, Lawrence Eng, UsaHalden Calculex Circular Slide Rule W Orig Case & InstructionsVintage Slide Rule: Pickett N4-es Vector Type Log Log Dual Base Speed In Case1960's~keuffel & Esser~deci-lon 68-1100~k&e Slide Rule W/originalVintage 1947-61 K&e Keuffel Esser Scientific Slide Rule Deci-lon W/ Leather CaseVintage Slide Rule: Pickett N4-es Dual Base Speed Rule In Case3 Vintage Pickett Slide Rule Lot Collection In Box Nib Model 120 W/ InstructionsVintage 6" Pickett Model 300 Pocket Slide Rule With Leather CaseVintage Raphoplex No 612 Made In France 6 Inch Slide Rule With Leather CaseK&e Keuffel & Esser Slide Rule Lot Of 3 AntiqueVintage Pocket Slide Rule: Pickett N600-es Log Log Speed Rule In Case 1962Vintage Slide Rule: K & E Deci-lon, 1962 Book, 186 Pgs.Vintage Keuffel & Esser (k&e) Slide Rule #4081-3 Log Log Duplex Decitrig W/ CaseSlide Rule - Sun Hemmi Japan - Hughes-owens #1771 Very Fine PieceVintage Circular Slide Rule Soviet Russian Ussr 1960-70s Vintage 1947 Keuffel & Esser 4081-2 Log Log Decitrig Slide Rule W Leather CaseStanley No 136 1/2 Boxwood Vernier Caliper Rule Slide GaugeVintage Slide Rule: Pickett N3-es Power Log Expontial In Case C. 1960Post Versalog 1460 Slide Rule And CaseAristo Maverick German Trig. Slide RuleSans & Streiffe Vintage No. 312 Bamboo Slide Rule & Case & Manual--no Reserve!Hemmi Sun Bamboo Slide Rule #259dAcumath Trig. Slide RuleK&e No. 68-1100 Decilon Slide Rule/case-10 InchK&e No. 4053-5 Slide Rule/case-20inch Mannheim ModelVintage K+e Keuffel & Esser Co No. 4181-1 Pocket Slide Rule W/ Leather CaseCircular Concise No 28 Slide RuleVintage Howitzer Cannon Graphical Firing Table Slide Rule Military How 155mm Vintage K&e Polyphase Slide Rule In Leather Case Keuffel & Esser CoPickett All Metal Slide RuleDatagraphix Circular Slide Rule/caseVintage C-thru S888 Japan Slide Rule In Plastic Case With InstructionsVintage Shure Brothers Reactance Slide RuleVintage K-e Slide Rule No.68 063 W/case Box & ManualPickett Slide RuleVintage Keuffel & Esser Slide Rule W/ Leather CaseVintage Drafting Tool Slide Rule, Never Used, Drafting Tool, Japan (ref.#1168)