Single-use plastic is having a significant environmental impact and its reduction is a mandatory step to reduce plastic pollution worldwide. Indeed, the time that a plastic item can persist in the environment is very long and it is well known that it can produce devastating effects in particular in seas and oceans. Moreover, production, use and disposal of plastic items have a significant impact also on the greenhouse effect; this can be estimated in a life cycle approach, by evaluating their carbon footprint. In this work, a review of the carbon footprint evaluation of different single-use plastic categories has been carried out, developing a methodology to immediately evaluate the benefits related to their substitution with compostable and bio-plastic and/or multiple-use items and materials. The result of the novel methodology developed is a certain number of matrixes, which can categorize impact values in order to compare them with replacement with bio-based plastic materials or multi-use things. Finally, the methodology was tested and validated through a case study, where a plastic reduction plan was proposed and implemented and the CO2 equivalent reduction was assessed, demonstrating a reduction potential related to a replacement by bioplastic or other materials equal, respectively, to 73% and 90%.