A cosmology calculator for the World Wide Web

A cosmology calculator that computes times and distances as a function of redshift for user-defined cosmological parameters has been made available online. This paper gives the formulae used by the cosmology calculator and discusses some of its implementation. A version of the calculator that allows one to specify the equation-of-state parameter w and w', and one for converting the light-travel times usually given in the popular press into redshifts, is also located at the same site.