This article presents the conceptualization of three dimensions surrounding reading: comprehensibility, readability, and legibility. On one hand, readability and legibility for the traceability of reading according to the text, and comprehensibility, on the other hand, as the symbiosis between text and reader. From the perspective of the reader (comprehensibility, ability, and level of a reader to understand a text as it also depends on the skills of the message receiver) and the text itself (legibility and readability or level of difficulty that a text per se entails through its intrinsic formal characteristics) generating two new formulas that define the terms of legibility and readability (specifically in Spanish) since that of comprehensibility exists today and is based on the Common European Framework of Reference for Languages (CEFR), with six levels ranging from A1 to C2 according to TEECLED. Two algorithms that respond to the previous concepts have been developed from the theoretical framework. The suggested formulas of both concepts, readability and comprehensibility, have been validated with texts published in the last 10 years by the Instituto Cervantes, classified by levels A1-C2. The results show that it coincides with the A1-C2 classification of the official DELE exam texts of the Instituto Cervantes in the last 10 years by an average of over 80%.