For practical purposes this paper is a presentation of old and new methods for evaluating the fractal dimension of one-variable function graphs: spectral method, Minkowski, box counting, intersection, ... Their efficiency is tested comparatively on well-known functions (Brownian noise, Weierstrass-Mandelbrot function). It appears that one of the fastest and most accurate algorithms is our new «variation method», based upon the use of horizontal structural segments On recense les methodes permettant de determiner la dimension fractale de graphes de fonctions d'une variable non derivable. On presente des methodes nouvelles dont l'efficacite est testee comparativement sur des fonctions connues (bruit brownien, fonction de Weierstrass-Mandelbrot). La methode de variation fondee sur l'utilisation de segments structurants horizontaux parait presenter les meilleures garanties de rapidite d'emploi et de precision du resultat