History of Slide Rules Timeline

(1614–Present)

This timeline traces how slide rules evolved from logarithmic principles into essential tools for engineering, science, navigation, and education before electronic calculators transformed computation. More Less

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Origins and early development

Logarithms inspire the slide rule

1620 - 1630

The slide rule was invented around 1620–1630, shortly after John Napier published the concept of the logarithm. Logarithmic relationships made it possible to transform multiplication and division into simpler addition and subtraction operations.

Image source: Slide rule

Edmund Gunter develops a logarithmic scale

1620

In 1620, Edmund Gunter of Oxford developed a calculating device with a single logarithmic scale. Used with additional measuring tools, it could perform multiplication and division.

Image source: Edmund Gunter

William Oughtred creates the slide rule

1622

Around 1622, William Oughtred of Cambridge combined two handheld Gunter rules. The resulting device was recognizably the modern slide rule.

Image source: William Oughtred

Oughtred's ideas are published

1632 - 1653

William Oughtred's slide-rule ideas became public through publications by his student William Forster in 1632 and 1653, helping disseminate the invention beyond Oughtred's immediate circle.

Technical innovations

Coggeshall creates a folding slide rule

1677

In 1677, Henry Coggeshall created a two-foot folding rule for timber measurement. Known as the Coggeshall slide rule, it expanded slide-rule use beyond purely mathematical inquiry.

Polyphase scales are introduced

1722 - 1755

Warner introduced two- and three-decade scales in 1722, and Everard added an inverted scale in 1755. A rule containing these features became known as a polyphase rule.

Roget invents the log-log slide rule

1815

In 1815, Peter Mark Roget invented the log-log slide rule. It included a scale displaying the logarithm of the logarithm, extending the range of calculations possible with the instrument.

Image source: Peter Mark Roget

The Mannheim arrangement becomes standard

1859 - 1900

The Mannheim rule became the standard slide-rule arrangement during the later 19th century and remained a common standard throughout the slide-rule era.

Image source: Amédée Mannheim

The Mannheim rule is created

1859

In 1859, French artillery lieutenant Amédée Mannheim created a more modern form of the slide rule. Its design benefited from production by a nationally prominent firm and adoption by the French Artillery.

Thacher introduces a cylindrical rule

1881

In 1881, American inventor Edwin Thacher introduced a cylindrical slide rule. Its much longer scale than standard linear rules allowed calculations to approximately four or five significant digits.

Image source: Slide rule

Cox invents the duplex rule

1891

William Cox invented the duplex slide rule in 1891. The Keuffel and Esser Company of New York produced the design.

Hemmi begins making bamboo slide rules

1895

In 1895, the Japanese firm Hemmi began making slide rules from celluloid-clad bamboo. The material was dimensionally stable, strong, and naturally self-lubricating.

Bamboo slide rules spread to Europe

1933

Celluloid-clad bamboo slide rules were introduced in Sweden in September 1933 and probably appeared in Germany only slightly earlier.

Hayner designs a Braille circular slide rule

1937

In 1937, physicist Lucy Hayner designed and constructed a circular slide rule in Braille, adapting the calculating instrument for users who were blind or visually impaired.

The Concise Company begins production

1954

The Concise Company of Tokyo began as a manufacturer of circular slide rules in July 1954 and continues to make and sell them today.

The Model 510 offers 20 scales

1970

Around 1970, an inexpensive B. C. Boykin Model 510 featured 20 scales, including 50-inch C-D multiplication and logarithmic scales.

Professional and specialized use

Bowditch describes a navigation sliding rule

1821

In 1821, Nathaniel Bowditch described a sliding rule in the American Practical Navigator. It combined scaled trigonometric functions on the fixed part with logarithmic sines and tangents on the slider for navigation problems.

Image source: Nathaniel Bowditch

Cameron introduces a nautical slide rule

1845

In 1845, Paul Cameron of Glasgow introduced a nautical slide rule capable of answering navigation questions, including calculations involving the right ascension and declination of the Sun and principal stars.

Engineering drives widespread slide-rule use

1870 - 1900

The growth of the engineering profession during the later 19th century drove widespread use of slide rules. Adoption began in Europe and eventually expanded throughout the United States.

A two-meter observatory slide rule is used

1880 - 1899

Astronomical work required highly precise computations. In 19th-century Germany, one observatory used a steel slide rule approximately two meters long to obtain greater precision.

Rabone catalogs a cattle gauge

1892

The John Rabone & Sons 1892 catalog listed a Measuring Tape and Cattle Gauge, a slide-rule-like device used to estimate a cow's weight from its measurements.

Shute works on the R100 airship

1924 - 1929

In the 1920s, novelist and engineer Nevil Shute Norway was Chief Calculator on the design of the British R100 airship for Vickers Ltd. from 1924. He later titled his autobiography Slide Rule.

Image source: Nevil Shute

Breitling introduces the Navitimer

1952

In 1952, Swiss watch company Breitling introduced the Navitimer, a pilot's wristwatch with an integrated circular slide rule specialized for flight calculations.

Image source: Breitling SA

The Department of Defense publishes a nuclear-effects rule

1962

A Department of Defense publication from 1962 included a special-purpose circular slide rule for calculating blast effects, overpressure, and radiation exposure from a specified atomic-bomb yield.

The Apollo 13 slide rule reaches space

1970

A model N600-ES slide rule was taken aboard Apollo 13 in 1970. It is now owned by the National Air and Space Museum.

Decline and legacy

The Wang LOCI-2 is introduced

1965

Wang Laboratories introduced the LOCI-2 in 1965. It used logarithms for multiplication and division, providing an electronic alternative to some slide-rule calculations.

Image source: Wang Laboratories

The HP 9100A is introduced

1968

Hewlett-Packard introduced the HP 9100A in 1968. This electronic calculator was among the increasingly capable machines that began to challenge slide rules for technical computation.

Image source: Hewlett-Packard 9100A

The HP-35 handheld calculator is introduced

1972

Hewlett-Packard introduced the pocket-sized HP-35 scientific calculator in 1972. It was the first handheld device of its type, though its initial price was $395.

Image source: HP-35

Low-cost electronic calculators make slide rules obsolete

1974 - 1976

Around 1974, lower-cost handheld electronic scientific calculators began making slide rules largely obsolete. By 1975, basic four-function calculators cost less than $50, and by 1976 the TI-30 scientific calculator sold for less than $25.

Slide rules leave Texas UIL competition

1980

1980 was the final year of University Interscholastic League competition in Texas to use slide rules. The UIL had originally been organized in 1910 for literary events before also becoming a governing body for school sports.

Image source: University Interscholastic League

Personal computers complete the transition

1980 - 1989

After the HP-35 became inexpensive in the mid-1970s, slide rules became largely obsolete. They were no longer in regular use by the advent of personal desktop computers in the 1980s.

Slide-rule enthusiasts continue using the instrument

2001

Even in the 21st century, some people continue to prefer a slide rule over an electronic calculator as a practical computing device.

A new prosthaphaeresis slide rule is conceived

2004

In 2004, education researchers David B. Sher and Dean C. Nataro conceived a new type of slide rule based on prosthaphaeresis, an algorithm for rapidly computing products that predates logarithms.

The Keuffel and Esser collection reaches MIT

2005

Around 2005, the collection of the Keuffel and Esser Company, formerly based in Hoboken, New Jersey, was donated to MIT. The donation substantially expanded the institution's existing holdings.

Image source: Keuffel and Esser

Aldrin's Apollo 11 slide rule is auctioned

2007

The N600-ES slide rule owned by Buzz Aldrin and flown with him to the Moon on Apollo 11 was sold at auction in 2007.

ThinkGeek releases replica straight slide rules

Sep 2009

In September 2009, online retailer ThinkGeek introduced its own brand of straight slide rules. The products were described as faithful replicas and individually hand tooled.

ThinkGeek replicas become unavailable

2012

The ThinkGeek straight slide rules introduced in 2009 were no longer available by 2012.

Faber-Castell sells remaining slide rules

2018

Faber-Castell retained slide rules in inventory and made them available for international purchase through its web store until mid-2018.

Image source: Faber-Castell