A carbon footprint calculator is a tool used to estimate the total amount of greenhouse gases, primarily carbon dioxide (CO2), emitted directly or indirectly by human activities into the atmosphere, typically measured in units of kilograms or metric tons of CO2 equivalent. These activities include energy consumption, transportation, food consumption, and other lifestyle choices.

The calculator usually prompts users to input various data points related to their activities, such as electricity usage, fuel consumption for vehicles, distance traveled via different modes of transportation, and dietary habits. Based on this input, the calculator calculates the associated emissions using predefined emission factors or algorithms.

The purpose of a carbon footprint calculator is to raise awareness about the environmental impact of individual actions and lifestyles. By quantifying their carbon footprint, individuals can better understand which activities contribute the most to their emissions and identify opportunities for reducing their environmental impact. Additionally, carbon footprint calculators often provide tips and suggestions for mitigating emissions, such as using energy-efficient appliances, opting for public transportation or carpooling, reducing meat consumption, and supporting renewable energy sources.