Chi-Square Quantiles

TOMS451 is a FORTRAN77 library which implements ACM TOMS algorithm 451, which evaluates quantiles of the Chi-Square probability distribution.

The text of many ACM TOMS algorithms is available online through ACM: or NETLIB:


x = chisqd ( p, n )
where P is the probability and N is the number of degrees of freedom.


TOMS451 is available in a FORTRAN77 version.

Related Data and Programs:

PROB, a FORTRAN90 library which contains numerous routines for handling the Chi square distribution and other probability distributions.

TEST_VALUES, a FORTRAN90 library which contains routines which return sample values of various functions, including the modified beta function, and the logarithm of the gamma function.


  1. Richard Goldstein,
    Algorithm 451: Chi-Square Quantiles,
    Communications of the ACM,
    August 1973, Volume 16, Number 8, pages 483-484.

Source Code:

Examples and Tests:

List of Routines:

You can go up one level to the FORTRAN77 source codes.

Last revised on 01 December 2005.