Online shopping is rapidly expanding, but assessing its carbon emissions impact across the entire supply chain and individual consumption is underdeveloped. This study introduces a framework using hierarchical cluster analysis, Life Cycle Assessment, and nested logit models to evaluate the environmental impact of online shopping. Combining online survey data and on-site supermarket survey data, it is found that the composition of shopping baskets influences shopping trip chain choice, whereas, for in-store shopping, the sizes of the baskets are associated with shopping trip lengths. Key contributors to online shopping emissions are transportation, packaging, and returns & exchanges. In contrast, in-store shopping emissions link to transportation, packaging, in-store operations. Shopping emissions primarily hinge on shopping baskets and shopping trip lengths. Total carbon emissions per consumer increase by 29 % for online shopping when shopping trip length to physical stores is under 2 km but decreases by 29 % and 50 % when it extends to 20 km and 40 km, respectively.