Inés María Barrio Cantalejo developed the Inflesz Scale to match results more accurately with the Szigriszt-Pazos Perspicuity Index. Barrio said the original formula, developed by Luz Mary Pazos and Francisco Szigriszt, used insufficient, non-representative, or random samples of texts to validate results.

The Inflesz scale was validated through a random selection of 210 publications from three categories: stationary magazines, school textbooks, and scientific magazines.

The scale uses five readability levels: "Difficult" (<40), "Slightly Difficult" (40-55), "Normal (Average)" (55-65), "Easy" (65-80), and "Very Easy" (>80). This scale is more aligned with Spanish reading habits and offers a more nuanced understanding of readability levels compared to its predecessors.

Range	Readability	US Grade Level	Spanish Education Level	Age Group	Reading Ease Score
P ≤ 40	Difficult	11th - 12th Grade	1º - 2º Bachillerato	16-18 year olds	11.5
40 < P ≤ 55	Slightly Difficult	9th - 10th Grade	3º - 4º ESO	14-16 year olds	9.5
55 < P ≤ 65	Average	7th - 8th Grade	1º - 2º ESO	12-14 year olds	7.5
65 < P ≤ 80	Easy	4th - 6th Grade	4º - 6º Primaria	9-11 year olds	4.5
P > 80	Very Easy	1st - 3rd Grade	1º - 3º Primaria	6-9 year olds	2.5

The Inflesz Scale outputs a number to find the reading level of a text. We added students' ages and grade levels to each readability level to help you visualize who your reader is.