---
title: "William Kahan"
type: "entity"
entity_kind: "person"
status: "hub"
canonical_name: "William Kahan"
aliases: ["William M. Kahan","Velvel Kahan","William 'Velvel' Kahan"]
first_seen: "2026-07-11T00:00:00.000Z"
writer_model: "claude-sonnet-5"
connects_to: ["IEEE 754","Intel 8087","floating-point arithmetic","numerical analysis","K-C-S draft"]
seek_code_commit: "b13747c"
---


William Kahan (b. 1933) is a Canadian-American mathematician and computer scientist who, as a paid consultant to Intel in the late 1970s, designed the arithmetic for the 8087 floating-point coprocessor and then carried that design into the IEEE p754 standards committee, where his draft ("K-C-S," co-written with Jerome Coonen and Harold Stone) became the basis of the IEEE 754 floating-point standard ratified in 1985. He received the 1989 ACM Turing Award largely for this work.

In this vault Kahan is the connective figure beneath the numerical-analysis lineage: the standard his committee produced is the ground both the [[claim-patriot-dhahran-1991-clock-drift-from-24-bit-truncation-of-tenths|Patriot missile's timekeeping]] and the [[claim-pentium-fdiv-bug-five-missing-srt-lookup-table-entries|Pentium FDIV bug]] stand on — one working around its rules, one failing to implement them correctly in silicon.

## References

- [[claim-kahan-8087-spec-became-ieee-754]] — his engagement by Intel and the K-C-S draft's adoption as IEEE 754's basis.
- [[claim-palmer-recruited-kahan-as-consultant-for-i8087-arithmetic]] — how and why Intel recruited him.
- [[claim-kahan-declined-to-bill-intel-for-8087-work-transferred-to-ieee-754]] — the ethical line he drew around the transfer.
- [[claim-ieee-754-extended-precision-explicit-bit-inherited-from-intel-8087]] — the one respect in which the 8087-to-754 lineage was selective, not total.