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    

Nice K & E Deci-lon 5 Slide RuleVintage Slide Rule Faber-castell 62/83 Slide Rule Germany NicePost Versalog 1461 Pocket Slide Rule And Versalog Instruction BookVintage~pickett N600-es Slide Rule~5 Inch W/original Leather CasePickett Fuller Traffic Aanalysis Slide Rule - Model 1050 Circular Slide Rule - Unknown Maker6 Slide Rule Books- Keuffel And Esser, Piockett And More Keufeel & Esser Mannheim Slide Rule. Three. Duetzgen Triangular Scale.Sun Hemmi P261 10" Advanced Engineering Duplex Slide RuleVintage Slide Rule Made By Keuffel & Esser Co. 68-1210 Log Log Duplex DectrigVintage 1959 Pickett Model N4-t All Metal Slide Rule With Leather Case 1 OwnerSun Hemmi No. 153 Slide Rule Japan Manual And Case Sweet CollectibleAntique A.w. Faber-castell? , Pencil Set W/slide Rule GermanyConcise Stadia Surveying Slide RuleFaber Castell Addiator With Slide RuleRare Pickett Georgia Iron Works Hydraulic Slide RuleSlide Rule Pickett & Eckel Model 4-es Dual Base Log Log 24 ScalesConcise Circular Slide Rule With Boeing LogoVintage Faber Castell Addiator 67/87 R.slide Rule, Calculator.germanyPickett N4-es Slide RuleVintage A.w.faber Castell Slide Rule In Original Case Super CondKeuffel & Esser Duplex Slide Rule With Case ~ Exc CondVintage Keuffel & Esser (k&e) 4081-3 Slide Rule S/n 719996 (with Magnifier)Pickett N500es Metal Log Log Slide Rule + Leather Case + DocumentsPickett Model 4es Metal Log Log Slide Rule + Leather Case- Picket Dual Base LogVintage 1952 Sun Hemmi Slide Rule Japan 1447 Simplex Post 10" Bamboo NrCircular Binary Slide Rule 1940 Copyright 1931 - 8.1/4" Diameter + ManualsOld School Hemmi Slide Rule And Leather CasePickett 510-t Business & Financial Slide RuleHigh Quality Model Pickett All Metal Slide Rule N 3-es Us Navy & Leather Case Sun Hemmi Bamboo Slide Rule 153 - Excellent ConditionKeuffel & Esser K&e 68 1565 Gp-12 Slide Rule With CaseVintage Goren Point Count Bidding Wheel Circular Slide Rule For BridgeVintage Acumath No. 400 Slide Rule Made In UsaEsso Imperial Oil True Course Wind Air Circular Slide Rule Air Navigation FuelFeisenthal Instruments Mark Viii-c Computer Circular Slide Rule Air NavigationVintage Pickett Simplex Trig Slide RuleVintage 1960s Precision Sterling 11" Slide Rule Usa School Business WorkPost Versalog 1460 Hemmi Slide Rule With Leather CaseVintage Model N-500-t Hi Log 12 Inch Pickett Metal Slide Rule With Leather CaseVintage Harco Circular Slide Rule W/ Card, Case & Manual NiceVintage Keuffel & Esser 4088-3 Slide Rule 1900 1908 PatentBrow Boveri Slide Rule, NPickett 903-t Vintage Slide Rule With Box And Manual - Very GoodKeuffel & Esser # 4055 Patent Date 1900 Slide Rule1949 Dated Aluminum 12" Pickett Slide Rule Mod. 800 With Leather CaseVintage Keuffel & Esser K&e Polyphase Slide Rule 4053-31949 Pickett And Eckel Slide Rule Apr. 12" LongNice 1950's Dietzgen N1734 Decimal Trig Type Log Log Slide Rule W/ Leather CaseK&e Slide Rule W/case& Inst Model4081-3sOld Dietzgen Maniphase Multiplex Trig Log Log 1732 Slide Rule - S/n 529986Telex E-6b Computer Dead Reckoning Computer, Slide RulePickett Slide Rule Model N902-es / Simplex Trig ~ With Black CaseVintage Pickett Microline 120 Student Slide Rule W/case, "how To Use" Book & BoxDietzgen Maniphase Multiplex Vector Type Log Log Rule Slide + Leather CaseVintage Keuffel & Esser K&e Slide Rule # 4161-3