On ecobalyse.beta.gouv.fr, choose "Simuler un produit textile" (Simulate a textile product) in regulatory mode, then answer 4 questions: the type of garment, the fabric composition (materials, proportions, recycled or not), the country of each stage (weaving or knitting, finishing and garment making are mandatory; spinning is optional) and, if you know it, the share of air transport. The tool displays a total score and its breakdown by life cycle stage within seconds. Each empty field receives a penalising default value (a range of 100,000 product references, spinning in an unknown country, a high share of air transport if garment making is outside Europe), so it is worth gathering supplier data before the final entry.
Read the source article: Ecobalyse calculator: what it is and how to use it in France