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: Pickett N3p Synchrolog In Box, Unsued W Instructions, CleanVintage Slide Rule: Fowler's Long Scale Calculator Double Sided, In Case C.1898Aristo Nuclear Slide Rule 10174. Near Mint! Very Rare! Echoes Of Cold War.Vintage Frederick Post Versalog Slide Rule #1461 W/caseAristo Studiolog 0969 Slide RuleUnusual Vintage Wooden Slide Rule Calculating Alcohol Customs Excise Dring FageVintage Pickett Slide Rule Model 6-t Statistical Quality Control With Case 12inVintage Slide Rule: Pickett Circular Slide Rule 107 Es In Case W InstructionsPickett / Lietz Circular Slide Rule 101-c W/case & Manual Excellent ConditionVintage Slide Rule: Pickett N600-t Log Log Speed Rule In Box With InstructionsPickett Slide Rule N4-es Log Vintage 1959 With Leather Case Pickett Eckel UsaVintage Slide Rule: Pickett #300 Pocket In Box, Unsued W Instructions, CleanFaber-castell German Slide RuleVintage Blackwell Average Speed Calculator/ Circular Slide Rule Rally LiverpoolVtg. Dietzgen Midget Circular Slide Rule Excellent W/ Manual Instructions CaseVintage Round Slide Rule Russia 1950 Germany Slide Rule Faber Castell Model 343 Sistem Baur Extremely Rare!*Incredible Picket 7 Foot Vintage Slide Rule! Classroom Or Advertisement Size!Vintage K E Keuffel Esser Co. Deci-lon Slide Rule 68 1100 W/ Leather CaseVintage Slide Rule: Pickett N4-es Vector Type Log Log Dual Base Speed In CaseSun Hemmi 5inch Pocket Slide Rule, CaseVintage Slide Rule: K & E N4041 W Magnifier In Case #0262691960's~keuffel & Esser~deci-lon 68-1100~k&e Slide Rule W/originalVintage Slide Rule: K & E Deci-lon, 1962 Book, 186 Pgs.Vintage Slide Rule: Pickett N4-es Dual Base Speed Rule In CaseVintage Slide Rule: Pickett N3-es Power Log Expontial In Case C. 1960Vintage K & E Deci-lon 10 Slide Rule Engineering Slide Rule #68 1100 Plus CaseHemmi Sun Bamboo Slide Rule #259dVintage 1947 Keuffel & Esser 4081-2 Log Log Decitrig Slide Rule W Leather CaseVtg Lutz No. 102 S Japan Made Engineering Logarithmic Bamboo Slide Rule MintSans & Streiffe Vintage No. 312 Bamboo Slide Rule & Case & Manual--no Reserve!Stanley No 136 1/2 Boxwood Vernier Caliper Rule Slide GaugeVintage Raphoplex No 612 Made In France 6 Inch Slide Rule With Leather CaseK&e Keuffel & Esser Slide Rule Lot Of 3 AntiqueCircular (round) Slide Rule Russian Soviet Vintage Calculator Kl-1 ExcVintage Keuffel & Esser (k&e) Slide Rule #4081-3 Log Log Duplex Decitrig W/ CaseVintage Slide Rule And Leather Case, K & EVtg Texas Instruments Sr-50 Slide Rule Calculator Ac Adapter Manual Case Box Slide Rule - Sun Hemmi Japan - Hughes-owens #1771 Very Fine PieceConcise Slide Rule No. 271Aristo Maverick German Trig. Slide RuleAcumath 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 CaseVintage Texas Instruments Ti-30 Slide Rule Calculator Red Led Box Manual 70sVintage Concise Circular Slide Rule No. 28 N With Original Case & ManualVintage Slide Rule Instructions: Dietzen How To Use, 18pgs, 1942 CleanVintage Howitzer Cannon Graphical Firing Table Slide Rule Military How 155mm Pickett All Metal Slide RuleVintage Lot Of 3 Drafting/engineering Tools, Bruning Slide Rule, Post Ruling PenDatagraphix Circular Slide Rule/caseVintage C-thru S888 Japan Slide Rule In Plastic Case With InstructionsVintage Shure Brothers Reactance Slide RulePickett Slide RuleVintage Drafting Tool Slide Rule, Never Used, Drafting Tool, Japan (ref.#1168)