# Calculation methodology The AWS Sustainability service quantifies estimated environmental impact (carbon, water) associated with the use of AWS cloud services and covers the full range of said services. The methodologies used to calculate the impact estimates are based on industry standards and have been verified by an independent third-party. The methodologies are updated over time based on evolving data, climate science, and more. To see the full methodology documents for the current version of the methodologies and the third-party verification letters see [Reports](https://sustainability.aboutamazon.com/reports) on the *Amazon Sustainability* page. When AWS releases a new version of the methodology, historical data is recalculated using the updated version to ensure accurate comparisons over time. The carbon emissions and water allocation estimates provided in the AWS Sustainability service currently cover the environmental impact of running workloads on AWS-operated infrastructure. Emissions associated with the development and maintenance of third-party software purchased through AWS Marketplace are not included, as those activities occur on the provider's own infrastructure. For services that run on AWS infrastructure but are billed through Marketplace subscriptions, coverage is being expanded. The carbon emissions and water withdrawals methodology pages dive deeper into each impact area’s calculation methodology: + [Carbon emissions](methodology-carbon.md) + [Water withdrawals](methodology-water.md)