A program listing of a subroutine for conversion of seven human physiological parameters: pH-pO2-pCO2-Hb-Ht-the subject's temperature T and the plasmaprotein content PP into whole blood base excess is detailed for use with a medium seized electronic calculator coupled with a data printer. The operating instructions are also given. The subroutine is self-contained and can easily accept a correction of the empirical factors which are in animals different from human. Its use was tested in a series of 36 clinical samples of blood and the results were compared wih those obtained on the same samples with three different nomograms. No statistically significant difference was found between the four methods.