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    

Pickett 600-es Dual Base Log Log All Metal Pocket Slide RuleVintage K+e K&e Deci-lon Keuffel & Esser Slide Rule 68 1100 Leather Case, BookSlide Rule - 4 Ft Long Yellow Pickett Teaching Classroom Slide Rule Nice ! Vintage Pickett & Eckel Slide Rule MagnifierVintage Lot Of 4 Pickett Hi Log Log Slide Rule Boxed N500t N500es Leather Cases Rare Russian Ussr Slide Rule Circular Kl-1 Vintage Faber Castell Addiator Darmstadt Pocket Slide Rule Calculator GermanyHemmi 251 Slide Rule - New1957 Vtg Pickett 101-c Dial Rule Circular Slide Rule With Pouch And ManualCircular Slide Rule, U.s. Government, Sama & Etani, Concise #600, 1968, CaseVintage Pickett Slide RuleVintage Boxed K+e Slide Rule Leather Case Model 4168 Keuffel & EsserAntique Boxwood Slide Rule 4-side 3-rule Square Cube Knot Spheroid Variety Vintage 1960's Pickett Slide Rule N 200-es Trig With Leather Case, Book & BoxVintage Concise Circular Slide Rule #28 For Electronics EngineersAtlas Circular Slide Rule Two Sided 8 1/4'' W/guide Free ShippingVintage Pickett Electronic Logarithmic Slide Rule – Made In UsaVintage Post Versalog Frederick 1460 Slide Rule With Leather Holster Vintage 1956 S.r.&s.e. Concrete Calculator/slide Rule / Advertising-decatur Ill.Sun Hemmi. Slide Rule.made In Occupied Japan. Leather Case. Frederick Post1441.Vintage Slide Rule No 4181-3, The Keuffels & Esser Co. Made In Usa, 3 PatentsVintage Post No. 1462 Slide Rule With CaseKeuffel & Esser K&e Slide Rule Model 322058 With Leather Case & BookVintage Trig Slide Rule Manual By M L Hartung For Pickett. Vintage Log Log Slide Rule Manual By M L Hartung For Pickett. Vintage Dual Base Slide Rule Manual By M L Hartung For Pickett. Acumath 400 Slide Rule With Vintage Lawrence Instruction Book 1940's UsaFredrick Post Versalog Slide Rule #1460l 10" With Leather Case1931 Gibson Midget Slide Rule W/ Case & InstructionsAntique 3d Sterling Silver Slide Rule Cuff Links Pat. PendingVintage ©1947 Keuffel & Esser Co. #4081-3 K+e Log Log Duplex Decitrig Slide RuleVintage K & E Keuffel Esser Beginners Slide Rule 4058 W Black CaseWeems & Plath Nautical Slide Rule 105