Due to the exclusion of the tobacco industry from the mandatory compliance framework of the national carbon market, and the consequent absence of sustained policy-driven mechanisms and data verification systems, China has not yet established carbon emission calculation standards specifically tailored to cigarette factories. This study systematically reviewed mainstream domestic and international carbon accounting methodologies, analyzed emission sources specific to cigarette factories across Scope 1 to Scope 3, and developed corresponding calculation methods. Based on statistical data from field research at actual cigarette factories, a complete annual carbon emission covering Scopes 1-3 was calculated for a case-study factory. Considering data availability, internal controllability within the tobacco industry, and the guidance value for the sector's green and low-carbon transition, this study proposes recommended carbon emission calculation boundaries and itemized calculation methods for cigarette factories, aiming to promote the accuracy and standardization of carbon emission calculations in cigarette factories.