Available Carbon Emissions units
- kilogram CO2e conversions
Kilogram of CO2 equivalent (kg CO2e) is the standard unit for expressing carbon footprint measurements. It quantifies greenhouse gas emissions by converting them to the equivalent warming impact of carbon dioxide over a specified timeframe.
- gram CO2e conversions
Gram of CO2 equivalent (g CO2e) is a small-scale carbon emissions unit. It is used to express the carbon footprint of individual products, food items, and short journeys where emissions are minimal.
- tonne CO2e conversions
Tonne of CO2 equivalent (t CO2e) is the standard large-scale unit for national and industrial carbon accounting. It is used in emissions trading schemes, sustainability reports, and international climate agreements.
- watt hour CO2e equivalent conversions
Watt hour CO2 equivalent is a carbon emissions unit expressing the greenhouse gas equivalent of producing one watt hour of electricity. It is used in energy labelling, lifecycle assessments, and grid carbon intensity calculations.
- kilowatt hour CO2e equivalent conversions
Kilowatt hour CO2 equivalent is a carbon emissions unit expressing the greenhouse gases produced per kilowatt hour of energy. It is widely used by electricity providers, EV charging calculators, and corporate sustainability reporting.
- megawatt hour CO2e equivalent conversions
Megawatt hour CO2 equivalent is a large-scale carbon emissions unit used to assess the environmental impact of power generation facilities, industrial processes, and energy-intensive operations.
Assumption: electricity-to-CO2 uses 0.445 kg CO2e per kWh (IEA, 2024; ≈2247 Wh per kg CO2e). Actual factors vary by country, grid mix, and year.
Full Carbon Emissions conversion matrix
| Unit | Equivalent in kilograms CO2e | kg CO2e | g CO2e | t CO2e | Wh→CO2e | kWh→CO2e | MWh→CO2e |
|---|---|---|---|---|---|---|---|
| kilogram CO2e | 1 kg CO2e | 1 | 1,000 | 0.001 | 2,247.19101124 | 2.24719101 | 0.00224719 |
| gram CO2e | 0.001 kg CO2e | 0.001 | 1 | 0.000001 | 2.24719101 | 0.00224719 | 0.00000225 |
| tonne CO2e | 1,000 kg CO2e | 1,000 | 1,000,000 | 1 | 2,247,191.01123596 | 2,247.19101124 | 2.24719101 |
| watt hour CO2e equivalent | 0.000445 kg CO2e | 0.000445 | 0.445 | 4.450000e-07 | 1 | 0.001 | 0.000001 |
| kilowatt hour CO2e equivalent | 0.445 kg CO2e | 0.445 | 445 | 0.000445 | 1,000 | 1 | 0.001 |
| megawatt hour CO2e equivalent | 445 kg CO2e | 445 | 445,000 | 0.445 | 1,000,000 | 1,000 | 1 |
About Carbon Emissions
Electricity and carbon intensity units
Real-world uses
Carbon emission units are used by governments, corporations, and individuals to measure environmental impact. Electricity grids report carbon intensity in grams of CO₂ equivalent per kilowatt-hour (gCO₂e/kWh). Companies calculate Scope 1, 2, and 3 emissions in tonnes of CO₂ equivalent for ESG reporting. Carbon offset markets trade credits representing one tonne of CO₂e each.
History
Carbon accounting emerged in the 1990s following the establishment of the IPCC in 1988 and the Kyoto Protocol in 1997, which created binding emission reduction targets. The concept of "CO₂ equivalent" was developed to compare the warming potential of different greenhouse gases using a common metric. The EU Emissions Trading System, launched in 2005, became the first large-scale carbon market.
Common mistakes
A frequent error is conflating carbon dioxide (CO₂) with carbon equivalent (CO₂e), which also accounts for methane, nitrous oxide, and other gases weighted by their global warming potential. People often apply a single emission factor globally, ignoring that grid carbon intensity varies enormously by country. Another mistake is double-counting emissions across Scope 2 and Scope 3 categories.
Measurement standards
The Greenhouse Gas Protocol, maintained jointly by the World Resources Institute and the World Business Council for Sustainable Development, is the de facto global standard for measuring and reporting greenhouse gas emissions across corporate, project, and product life-cycle scopes.
Did you know?
A single transatlantic round-trip flight from London to New York generates roughly 1.6 tonnes of CO₂ per passenger — nearly a quarter of the average annual carbon footprint of a person in France.