Scope 1, 2 & 3 Emissions Calculator

The scopes framework partitions an organisation's greenhouse gas inventory by who controls the emitting source. Scope 1 covers direct emissions from owned or controlled sources, such as natural gas burned in a boiler at about 5.3 kg CO2e per therm or diesel in a fleet vehicle at roughly 10.21 kg CO2e per gallon. Scope 2 covers indirect emissions from purchased electricity, steam, heating and cooling, calculated as consumption multiplied by a grid emission factor; the United States average sits near 0.42 kg CO2e per kWh, but regional factors range from under 0.05 in hydro-dominated grids to above 0.7 in coal-heavy ones. Scope 3 covers everything else in the value chain, divided across 15 defined categories including purchased goods and services, business travel, employee commuting and use of sold products. The scope split exists to prevent double counting, since one company's Scope 2 is the power generator's Scope 1. Scopes are additive within an entity but must not be naively summed across a supply chain. Scope 3 is usually the largest share, commonly 70 to 90 percent of the total for retailers and financial firms, and also the least certain. This calculator estimates it with a spend-based factor of 0.4 kg CO2e per dollar, a screening approach derived from environmentally extended input-output models. Spend-based figures are convenient but coarse: they cannot distinguish an efficient supplier from an inefficient one at the same price, and they move with inflation rather than with physical change. Serious reporting migrates to supplier-specific or activity-based data as it becomes available.

The scopes concept comes from the Greenhouse Gas Protocol, a partnership launched in 1998 by the World Resources Institute and the World Business Council for Sustainable Development to end the proliferation of incompatible corporate carbon accounting methods. The first edition of the Corporate Accounting and Reporting Standard appeared in 2001, and the revised edition of 2004 established the Scope 1, 2 and 3 vocabulary in the form still used today. The International Organization for Standardization drew on that work for ISO 14064-1, published in 2006, giving the approach a formal standards-body counterpart for organisation-level quantification and reporting. Value chain accounting was left deliberately optional at first because it was considered too difficult to measure. That changed with the Corporate Value Chain (Scope 3) Standard in 2011, which defined the 15 categories and gave companies a consistent way to draw boundaries around indirect emissions. The Scope 2 Guidance of 2015 added the distinction between location-based accounting, using average grid intensity, and market-based accounting, which credits contractual instruments such as renewable energy certificates. Adoption accelerated as CDP disclosure requests, the Science Based Targets initiative founded in 2015, and later mandatory regimes including the EU Corporate Sustainability Reporting Directive and the ISSB standards all built their requirements directly on the GHG Protocol scope definitions.