This review article provides a comprehensive overview of acne grading scales used in 2023. Acne is a common skin condition that significantly affects quality of life, and accurate assessment is crucial for treatment and management. The authors review various acne severity assessment scales, including the Pillsbury scale, Cook's acne grading scale, Leeds acne grading system, Global Acne Grading System, and investigator's global assessment. They discuss the characteristics, advantages, limitations, and applicability of these scales. The ideal acne grading scale should be objective, accurate, comprehensive, easy to use, and applicable in various clinical and research settings. Current technologies, such as artificial intelligence, could contribute to the development of ideal acne grading scales. Acne severity can be assessed through global acne severity grading, acne lesion counting, and multimodal digital imaging. Global severity grading compares a patient's presentation with text descriptions or photographs. Acne lesion counting is typically performed on-site by tallying the number of different lesion types. Multimodal digital imaging evaluates lesion types, erythema, and pigmentary changes using photographic equipment. The advantages and disadvantages of these approaches are summarized in Table 1. The ideal acne grading scale should be simple, accurate, reproducible, and less time-consuming. The authors identified core domains for an ideal acne global grading scale (AGGS) through an online Delphi process. Current FDA scales, as well as earlier scales, can provide a framework for developing ideal scales. The history of acne grading scales is reviewed, including the first published acne grading system in 1956, the Leeds technique in 1998, and the Global Acne Grading System (GAGS) in 1997. The GAGS is a simple, accurate, and reproducible scale that classifies acne severity into mild, moderate, severe, or very severe. The authors also discuss the development of new acne grading systems, including the Korean Acne Grading System (KAGS) in 2004, the Investigator Global Assessment (IGA) scale in 2005, and the Comprehensive Acne Severity Scale (CASS) in 2007. The Spanish Acne Severity Scale (EGAE) and the Truncal Acne Severity Scale (TRASS) are also reviewed. The TRASS is a new method for assessing the severity of truncal acne, based on three subscores: severity based on disease and family history, acne severity, and impact on the patient's quality of life. The authors conclude that acne grading scales are diverse and have limitations. New acne assessment methods are needed to evaluate various aspects of acne severity. Training healthcare providers in acne severity assessment is important, and the use of acne grading scales by well-trained raters will improve the consistency of results. Future research on AI-based acne grading scales is expected to lead to an accurate, easy-to-use, and time-saving method for assessingThis review article provides a comprehensive overview of acne grading scales used in 2023. Acne is a common skin condition that significantly affects quality of life, and accurate assessment is crucial for treatment and management. The authors review various acne severity assessment scales, including the Pillsbury scale, Cook's acne grading scale, Leeds acne grading system, Global Acne Grading System, and investigator's global assessment. They discuss the characteristics, advantages, limitations, and applicability of these scales. The ideal acne grading scale should be objective, accurate, comprehensive, easy to use, and applicable in various clinical and research settings. Current technologies, such as artificial intelligence, could contribute to the development of ideal acne grading scales. Acne severity can be assessed through global acne severity grading, acne lesion counting, and multimodal digital imaging. Global severity grading compares a patient's presentation with text descriptions or photographs. Acne lesion counting is typically performed on-site by tallying the number of different lesion types. Multimodal digital imaging evaluates lesion types, erythema, and pigmentary changes using photographic equipment. The advantages and disadvantages of these approaches are summarized in Table 1. The ideal acne grading scale should be simple, accurate, reproducible, and less time-consuming. The authors identified core domains for an ideal acne global grading scale (AGGS) through an online Delphi process. Current FDA scales, as well as earlier scales, can provide a framework for developing ideal scales. The history of acne grading scales is reviewed, including the first published acne grading system in 1956, the Leeds technique in 1998, and the Global Acne Grading System (GAGS) in 1997. The GAGS is a simple, accurate, and reproducible scale that classifies acne severity into mild, moderate, severe, or very severe. The authors also discuss the development of new acne grading systems, including the Korean Acne Grading System (KAGS) in 2004, the Investigator Global Assessment (IGA) scale in 2005, and the Comprehensive Acne Severity Scale (CASS) in 2007. The Spanish Acne Severity Scale (EGAE) and the Truncal Acne Severity Scale (TRASS) are also reviewed. The TRASS is a new method for assessing the severity of truncal acne, based on three subscores: severity based on disease and family history, acne severity, and impact on the patient's quality of life. The authors conclude that acne grading scales are diverse and have limitations. New acne assessment methods are needed to evaluate various aspects of acne severity. Training healthcare providers in acne severity assessment is important, and the use of acne grading scales by well-trained raters will improve the consistency of results. Future research on AI-based acne grading scales is expected to lead to an accurate, easy-to-use, and time-saving method for assessing