Readability calculator.

Evidence: The Flesch readability formula (1948) was adapted for Spanish by Fernández Huerta (1959). These formulas only measure sentence and word length: they do not tell you whether a text is understood, and they do not replace easy-read guidelines (UNE 153101:2018 EX), which recommend short sentences with one idea each and plain vocabulary. For Spanish, the INFLESZ scale is also used (Barrio-Cantalejo et al., 2008).

Flesch, R. (1948). J. of Applied Psychology. · Kincaid, J.P. et al. (1975). Derivation of new readability formulas. · Fernández Huerta, J. (1959). Escritura. · Barrio-Cantalejo, I.M. et al. (2008). Validación de la escala INFLESZ. An. Sist. Sanit. Navar., 31(2). · UNE 153101:2018 Lectura Fácil.

Level of evidence: B (partial support). Basis: Published formulas: Flesch (1948), Flesch-Kincaid (1975) and Fernández Huerta’s Spanish adaptation (1959). Limits: They measure sentence and word length, not whether the text is understood nor the effect of dyslexia. In Basque it only gives counts.