William M. Kahan

Professor Emeritus


William "Velvel" Kahan was born in Canada and attended the University of Toronto for both his undergraduate and graduate studies in mathematics, and was eventually hired there as a professor. He joined the Berkeley faculty in 1968 with a joint appointment in the Math Department and as a member of the new Computer Science Department in the College of Letters and Science--before it merged with the EECS Department in the College of Engineering in 1973. He retired from the University in 2008. Kahan was instrumental in creating the IEEE 754-1985 standard for floating-point computation in the late 1970s and early 1980s. He developed a program called "paranoia' in the 1980s to test for potential floating point bugs and developed the Kaham summation algorithm which helps minimize errors introduced when adding a sequences of finite precision floating point numbers. Kahan won the ACM A.M. Turing Award in 1989.


  • 1958, Ph.D., Mathematics, University of Toronto
  • 1956, Master's, Mathematics, University of Toronto
  • 1954, B.A., Mathematics, University of Toronto

Selected Publications

Awards, Memberships and Fellowships