Convert g CO₂(e) to kg
| g | kg |
|---|---|
| 0.5 | 0.0005 |
| 1 | 0.001 |
| 1.5 | 0.0015 |
| 2 | 0.002 |
| 3 | 0.003 |
| 5 | 0.005 |
| 10 | 0.01 |
| 20 | 0.02 |
| 50 | 0.05 |
| 100 | 0.1 |
Each row uses the same factor as the converter above: 1 g = 0.001 kg.
Small, everyday footprints — a web search, a product’s carbon label, a mile of driving — are measured in grams of CO₂(e), while personal and product totals are in kilograms. The conversion is the simplest there is: 1 kilogram = 1,000 grams, so to turn grams into kilograms you divide by 1,000. It applies identically to CO₂ and CO₂e, because scaling a mass doesn’t depend on which gas it is.
To convert grams of CO₂(e) to kilograms, divide by 1,000 (1 kg = 1,000 g). So 250 g CO₂e = 0.25 kg CO₂e. To go the other way, multiply kilograms by 1,000.
kg = g ÷ 1,000. Reverse: g = kg × 1,000. Both are exact SI units, so there is no rounding — one kilogram is precisely 1,000 grams. The same factor applies whether the mass is CO₂ or CO₂e.
| Grams | ÷ 1,000 | Kilograms |
|---|---|---|
| 1,000 g | ÷ 1,000 | 1 kg |
| 500 g | ÷ 1,000 | 0.5 kg |
| 100 g | ÷ 1,000 | 0.1 kg |
| 1 g | ÷ 1,000 | 0.001 kg |
g to kg CO₂ conversion table
The table reads both ways — grams to kilograms on the left (÷ 1,000), kilograms back to grams on the right (× 1,000).
| g CO₂e | → kg (÷ 1,000) | kg CO₂e | → g (× 1,000) |
|---|---|---|---|
| 1 | 0.001 | 1 | 1,000 |
| 10 | 0.01 | 5 | 5,000 |
| 100 | 0.1 | 10 | 10,000 |
| 500 | 0.5 | 100 | 100,000 |
| 1,000 | 1 | 1,000 | 1,000,000 |
Where grams of CO₂ are used
Grams are the unit for anything small enough that a kilogram would be mostly zeros. Product carbon labels quote grams of CO₂e per item; digital footprints — an email, a web search, an AI query — are grams or fractions of a gram; and vehicle tailpipe standards are set in grams of CO₂ per kilometre. Once those add up to a person’s daily or a product’s total footprint, kilograms take over.
| Small footprint | g CO₂ | kg CO₂ |
|---|---|---|
| An AI / LLM query | ≈ 0.14 | 0.00014 |
| Charging a smartphone | ≈ 12 | 0.012 |
| Driving 1 mile (average US car) | ≈ 393 | 0.393 |
| Burning 1 gallon of gasoline | ≈ 8,887 | 8.887 |
CO₂ or CO₂e — the factor is the same
Because this is a pure mass conversion, dividing by 1,000 applies to CO₂, to CO₂e, or to any single greenhouse gas — CO₂e simply means the gases have already been combined into a CO₂-equivalent mass using their global warming potentials. It does not, however, convert carbon to CO₂: one gram of carbon becomes about 3.664 grams of CO₂ when oxidised, a separate step handled by the carbon-to-CO₂ converter.
Frequently Asked Questions
Divide the grams by 1,000. For example, 250 g CO₂e ÷ 1,000 = 0.25 kg CO₂e. To reverse it, multiply kilograms by 1,000. The factor is exact and applies to CO₂ and CO₂e alike.
Exactly 1,000. The gram and kilogram are SI units, with the kilogram defined as 1,000 grams — the same for CO₂ as for anything else.
Grams suit small, per-item footprints. Product carbon labels quote grams of CO₂e per item, digital actions like a web search or AI query are a fraction of a gram to a few grams, and vehicle standards are set in grams of CO₂ per kilometre. Convert to kilograms once the numbers grow to a personal or product total.
On its own, no — a single AI query is around 0.14 g and a web search a few tenths of a gram. The point of the gram is scale: billions of small actions add up to kilograms, tonnes and beyond, which is why footprints are tracked at whatever unit keeps the number readable.
No. Dividing a mass by 1,000 doesn’t depend on which gas it is, so the factor is identical for CO₂, CO₂e or any single greenhouse gas. CO₂e just means the different gases have already been combined into a CO₂-equivalent mass using their global warming potentials.
No. This converter changes the unit of mass (g to kg) but not the substance. One gram of carbon becomes about 3.664 grams of CO₂ when it is oxidised, because the carbon picks up two oxygen atoms — a separate conversion handled by the carbon-to-CO₂ converter.