This document, that is only available in English, is destined to the users of the Carbon Calculator and presents the general principles of the uses of the tool. The guide allows the user to become familiar with the recommendations that are specific to each module, and according to a progression in the different steps of the diagnostics, from collecting data to providing to the final results given by the Carbon Calculator. Reading this guide will allow the users optimal use of the tool for results with higher robustness.