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William Kahan
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William Kahan

Mathematician known as the father of floating-point arithmetic

5 June 1933 Canada Verified by our editors
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Age
93 yrs
Birthday in 211 days
Works listed
2
Technical standard, Algorithm
Honours
2
Most recent 2000
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William Kahan is a Canadian mathematician and computer scientist who was the main architect of the IEEE 754 standard for floating-point arithmetic, the way virtually every computer handles decimal numbers. He received the Turing Award in 1989.

Biography

Education

Kahan studied at the University of Toronto, earning his PhD in 1958, and worked on the university’s early FERUT computer.

Making numbers reliable

In the 1970s computers handled fractional numbers in incompatible ways, so the same program could give different answers on different machines. Working with Intel on the 8087 maths co-processor, Kahan designed careful rules for rounding, special values such as infinity and NaN, and gradual underflow.

IEEE 754

His design became the basis of the IEEE 754 standard of 1985, now used by almost all processors. It made numerical software portable and more trustworthy.

Berkeley

Kahan has taught at the University of California, Berkeley, since 1968. He is also known for the Kahan summation algorithm, which reduces rounding errors when adding many numbers, and for his work on calculators at Hewlett-Packard.

Timeline

  1. 1933

    Born in Toronto, Ontario, Canada

  2. 1958

    PhD from the University of Toronto

  3. 1968

    Joins UC Berkeley

  4. 1976

    Begins consulting for Intel on the 8087

  5. 1985

    IEEE 754 standard adopted

  6. 1989

    Turing Award

  7. 2000

    IEEE Emanuel R. Piore Award

Notable works

  • 1985

    IEEE 754 Technical standard

  • 1965

    Kahan summation algorithm Algorithm

Awards and honours

  • Turing Award

    1989

  • IEEE Emanuel R. Piore Award

    2000

Did you know?

  1. 1

    “NaN” means “not a number” — a special value his standard defined.

  2. 2

    He helped design the maths in HP’s scientific calculators.

  3. 3

    He has been a strong critic of careless floating-point programming.

Connections

Also born on 5 June

Frequently asked

Who is William Kahan?

William Kahan is a Canadian mathematician and computer scientist who was the main architect of the IEEE 754 standard for floating-point arithmetic, the way virtually every computer handles decimal numbers. He received the Turing Award in 1989.

How old is William Kahan?

William Kahan is 93 years old, born on 5 June 1933 in Toronto, Ontario, Canada.

Where is William Kahan from?

William Kahan was born in Toronto, Ontario, Canada.

What is William Kahan known for?

William Kahan is best known for The IEEE 754 floating-point standard; numerical analysis; Turing Award 1989.

What awards has William Kahan received?

Notable honours include Turing Award (1989), IEEE Emanuel R. Piore Award (2000).

References

  1. William Kahan — Wikipedia. Wikipedia. Retrieved 4 November 2026.
  2. William Kahan — Britannica. Encyclopaedia Britannica. Retrieved 4 November 2026.
  3. Official website. www.cs.berkeley.edu. Retrieved 4 November 2026.
  4. William Kahan (Q92782) — structured data. Wikidata. Retrieved 4 November 2026.

Includes material from the Wikipedia article “William Kahan”, licensed under CC BY-SA 4.0. That text is available under the same licence. Learn more

External links

Official website Website Wikipedia
Filed under Numerical analysisTuring AwardUC Berkeley Computer ScientistMathematicianProfessor

About this profile

Cite this page

“William Kahan.” TrackFame, last updated 5 November 2026. https://trackfame.com/person/william-kahan

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