Along with the improvement of the world’s industry and technology, the requirement of various typefaces and fonts in different tones in printed texts, as well as the development of digital platforms, including sites, applications, social media, etc., font design is highly regarded as one of the important branches of graphic design these days. Font designers attempted to create new typefaces and fonts for contemporary and modern applications by using the face and rules of Iranian calligraphy. Iranian calligraphy art is a precious treasure of diverse and pristine forms. The main and important source of type designers is the rich and full of formal creations of masterpieces of calligraphy in Islamic lands, especially in Iran. Iranian Naskh script, due to its remarkable compliance with the ratio and ease of reading and having unique formal features and ease of writing in long texts has caused a significant growth in the acceptance of type designers for inspiration from this script in the design of Iranian fonts in the present era. In the meantime, the Iranian Naskh script is an important source of adaptation for most fonts published in recent decades, as it complies with most of the calligraphy rules, while advantaging aesthetics and ease of reading and writing, as well as having the spirit of Iranian art. In addition, the creation of new and updated descendants of Iranian manuscripts is strong evidence of realizing the dynamism and vitality of Persian calligraphy during the past ages. At present, there are very few written and scientifically substantiated sources in the field of knowing the capabilities of calligraphy for use in new media, especially graphic design, as well as criticism, analysis, and evaluation of published fonts based on the rules of Iranian calligraphy. The conducted research mainly focused on the discussion of typography and calligraphy for specific paradigms in some periods of Iranian art history and techniques related to this field. By studying and reviewing the valuable research in the field of calligraphy and typography, no independent research has been found on matching the Iranian Naskh script with the fonts derived from it. Therefore, the present study seeks to express the percentage of conformity of new fonts with the Iranian Naskh script by expanding the twelve rules of calligraphy included in the treatise of Adaab al-Mashaq and adding 4 other rules as indicators of adaptation. This research aims to answer three questions: 1. what do Iranian Naskh script characteristics have in common with Harir, Vije, Mizan, and Ahang typefaces? 2. What kind of analysis can be presented about the similarities and differences between the Iranian script and the Harir, Vije, Mizan, and Ahang typefaces? 3. How to evaluate the aspects of adaptation and transformation of Iranian calligraphy in the design of Harir, Vije, Mizan, and Ahang typefaces? In this research, firstly, the twelve rules of calligraphy contained in the treatise of Adab-al-mashgh are introduced as a theoretical framework, then the degree of overlap of the fonts taken from the Naskh Script of Harir, Vije, Mizan, and Ahang with the rules governing calligraphy is studied via descriptive-analytic methodology in a comparative approach. Knowing the characteristics, and analyzing the capabilities, similarities, and changes of today's fonts compared to the Iranian script is one of the goals of this research. Evaluating the design quality of today's fonts using the transformation of Iranian script is one of the necessities of the research. Iranian font designers have created fonts with precise references using the rules of Iranian calligraphy, which are very important in terms of aesthetics, function, and form. The current research adapted the indices in the manuscript as "A" and the effectiveness of these rules on the Harir, Vije, Mizan, and Ahang typefaces as font “B” by applying the twelve rules of calligraphy including the treatise of Adaab al-Mashaq. The results of the research indicated that the Iranian script in matching with Harir, Vije, Mizan, and Ahang typefaces is in nine indexes consistent with the Iranian calligraphy rules. Those few differences in Iranian Naskh script with Harir, Vije, Mizan, and Ahang typefaces can be attributed to the change of tastes due to the passage of time and the expression of new and contemporary needs; as well as the freedom of type designers to add or remove faces to express creativity and innovation, and in some ways expanding the technology of implementation and development of the new fonts. Although this research only analyzed the level of letter design, it is hoped that researchers interested in the field of typography and calligraphy will try to introduce the capabilities of this valuable treasure by taking into account the composition and typesetting of the manuscript in comparison with Iranian fonts.