This is the online supplement for a series of studies aimed at creating the Product Aesthetics Inventory. Aesthetics is essential to the design of products. Nevertheless, aesthetic quality is often assessed with inaccurate, ad-hoc scales. Therefore, we have developed the Product Aesthetics Inventory (PAI) and its short version the PAI-S. A pre-study using face-to-face interviews (N = 6 design experts, N = 4 product users) served as basis for the development of test items. The resulting item battery was then used by N = 6002 persons in an online survey to evaluate various types of household appliances. In Study 1, n = 3000 of those participants’ data were used to determine the number of product aesthetics factors and to select the optimal items by combining exploratory graph analysis (EGA) and confirmatory factor analysis (CFA) approaches. We found an eight-factor structure consisting of the dimensions Visual aesthetics, Operating elements, Logo, Feedback sounds, Operating sound, Haptic, Interaction aesthetics, and Impression. In Study 2, we confirmed this structure by a CFA with the remaining n = 3002 participants, resulting in excellent model fit. Further, construct validity was confirmed by correlations with other established aesthetic scales, intentions, and general judgments. In both studies, strict measurement invariance was achieved across four household appliances, which further highlights the psychometric quality of the newly developed scales. In Study 3 (N = 1028), we demonstrated that most of the PAI factors as well as reliability, validity, and measurement invariance findings generalized to power tools, office equipment, and home entertainment devices. This online supplement includes Questionnaire templates for PAI and PAI-S in English and German Analysis templates (Excel) for calculating scales and sum values based on raw data in English and German Analysis scripts of our studies (R) A codebook describing all instructions and items of study 3 Raw data (anonymised) of study 3 (Note: The raw data contains only the information of persons who have agreed to be included in the analysis. Some demographic information was deleted to ensure anonymity.) A supplementary table with the list of original items sorted in categories and with abbreviations used, reasons for exclusion, and information on inclusion in the short scale.