In this software the so-called Goodman-Martinez-Thompson correlation number — 584,283 — is the default correlation number, but you can easily use any other. This software also allows specification of such comparatively arcane matters as the year-bearer system and the haab month base number (which are fully explained in the user manual).

Different systems are used in the various codices. The system used in the Dresden Codex ("Tikal") differs from that used in the Madrid Codex ("Mayapan"), and the system presupposed in the books of Dr. José Argüelles ("Yucatan") differs from both. Thus anyone seriously interested in matters involving the Maya Calendar needs to be able to convert Maya dates in more than one system.