Published online by Cambridge University Press: 20 January 2017
A Fortran computer program is presented that converts Lowland Maya Calendar Round dates to their equivalent Long Count dates, and the reverse, for the period 1139 B.C. - A.D. 2012 [5.0.0.0.0 to 13.0.0.0.0.]. Additional features include a calculation of the number of days that separate the submitted Long Count date from the completion dates of the prior three important calendric cycles [Sacred Round, Civil Year, and Calendar Round]. This program supplements an earlier Long Count-Gregorian conversion program [Sidrys et al. 1975].