gram CO2e (g CO2e)
1 gram CO2e = 0.001 kilograms CO2e
What is gram CO2e?
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.
Notes: Metric unit
Real-world uses
Gram CO2e is used for per-item emissions of small consumer products, per-kilometre vehicle emission ratings (e.g., 120 g CO2e/km for a car), and per-serving food carbon labels. EU vehicle regulations set fleet-wide targets in g CO2/km.
History
Gram-scale CO2e reporting emerged with product carbon labelling initiatives in the 2000s. Tesco briefly labelled products in g CO2e in 2007, and the EU adopted g CO2/km standards for vehicle emissions in 2009, driving widespread use of this unit.
Common mistakes
Overlooking the scope of emissions measured—g CO2e/km for a car might cover only tailpipe emissions (tank-to-wheel) or the full lifecycle (well-to-wheel), giving very different numbers. Always check the system boundary.
When is this conversion used?
Converting gram CO2e to kilogram CO2e is useful in the carbon emissions domain when comparing values across different measurement standards or applying formulas that require a specific unit.
How to convert gram CO2e to kilogram CO2e
To convert gram CO2e to kilogram CO2e, multiply the value by 0.001.
Conversion formula (from base unit)
x * 0.001
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.
| grams CO2e | kilograms CO2e |
|---|---|
| 0.1 | 0.0001 |
| 0.5 | 0.0005 |
| 1 | 0.001 |
| 2 | 0.002 |
| 5 | 0.005 |
| 10 | 0.01 |
| 25 | 0.025 |
| 50 | 0.05 |
| 100 | 0.1 |
| 250 | 0.25 |
| 500 | 0.5 |
| 1,000 | 1 |
Full gram CO2e conversion table
| Unit | Value | Factor |
|---|---|---|
| kilogram CO2e | 1 g CO2e = 0.001 kg CO2e | × 0.001 |
| tonne CO2e | 1 g CO2e = 0.000001 t CO2e | × 0.000001 |
| watt hour CO2e equivalent | 1 g CO2e = 2.24719101 Wh→CO2e | × 2.24719101 |
| kilowatt hour CO2e equivalent | 1 g CO2e = 0.00224719 kWh→CO2e | × 0.00224719 |
| megawatt hour CO2e equivalent | 1 g CO2e = 0.00000225 MWh→CO2e | × 0.00000225 |