Convert kg CO₂(e) to Tonnes
| kg | t |
|---|---|
| 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 kg = 0.001 t.
Emissions activity data usually arrives in kilograms — from fuel receipts, sub-meters and emission-factor tables — but corporate GHG reports are published in tonnes. Converting kg CO2(e) to tonnes is a single division, yet it is one of the most common places an inventory picks up an order-of-magnitude error. This page does the maths for you and explains where the two units belong.
To convert kilograms of CO2(e) to tonnes, divide by 1,000: tonnes = kg ÷ 1,000. So 2,500 kg = 2.5 t. This is the metric tonne used in all GHG reporting — not the US short ton or UK long ton — and the factor is the same for CO2 and CO2e.
How to convert kg CO₂(e) to tonnes
The metric tonne is defined as exactly 1,000 kilograms, so the conversion is a fixed ratio with no rounding and no dependence on temperature, pressure or gas type:
tonnes CO2(e) = kilograms CO2(e) ÷ 1,000 · and in reverse: kilograms = tonnes × 1,000
A delivery van burns diesel over a quarter, and the mobile-combustion calculation returns 4,720 kg CO2e. To enter it on the tonnes basis your GHG report expects:
| Step | Working | Result |
|---|---|---|
| Activity result | from the calculator | 4,720 kg CO2e |
| Divide by 1,000 | 4,720 ÷ 1,000 | 4.72 t CO2e |
| Report line | rounded to 2 dp | 4.72 tCO2e |
kg ↔ tonnes CO₂(e) conversion table
A quick reference across the magnitudes a real inventory spans — from a single appliance to a facility total. The table reads both ways: find your figure in either column.
| Kilograms CO2(e) | Tonnes CO2(e) |
|---|---|
| 1 kg | 0.001 t |
| 10 kg | 0.01 t |
| 100 kg | 0.1 t |
| 500 kg | 0.5 t |
| 1,000 kg | 1 t |
| 10,000 kg | 10 t |
| 100,000 kg | 100 t |
| 1,000,000 kg | 1,000 t (1 kilotonne) |
Why the kg/tonne distinction matters in GHG accounting
Reports are in tonnes; your data is in kilograms
The GHG Protocol, the UK’s DEFRA/DESNZ conversion factors, CDP disclosures and ISO 14064-1 inventory reporting all express results in tonnes of CO2 equivalent (tCO2e). But the raw activity data feeding them — litres of fuel, kWh of electricity, kilograms of refrigerant — is multiplied by emission factors that very often output grams or kilograms. Somewhere between the meter reading and the disclosure, a kg→tonne conversion has to happen. Doing it once, cleanly, at the right step is what keeps a roll-up across scopes internally consistent.
The order-of-magnitude trap
A missing or duplicated ÷1,000 misstates a line item by a factor of a thousand. Report 4,720 kg as “4,720 tonnes” and a single van out-emits a small factory; drop the conversion the other way and a facility total vanishes into a rounding error. Because both numbers look plausible in isolation, these errors survive review. Fix the unit at the point of entry and keep every line on the same basis before you sum.
“Tonne” is not “ton”
Throughout GHG accounting, tonne means the metric tonne = 1,000 kg. Two other units share the spelling and cause silent errors when data crosses regions:
| Unit | In kilograms | Used for GHG reporting? |
|---|---|---|
| Metric tonne (t) | 1,000 kg | Yes — the reporting standard |
| US short ton | 907.18 kg | No — US non-GHG contexts |
| UK/imperial long ton | 1,016.05 kg | No — legacy imperial |
If your source data is in short or long tons, convert to metric tonnes before applying the ÷1,000 logic on this page — a dedicated short-ton and long-ton converter covers that step.
CO₂ vs CO₂e: what the “(e)” changes (and what it doesn’t)
This converter is written “CO2(e)” because the mass scaling is molecule-agnostic: dividing kilograms by 1,000 gives tonnes whether the mass is pure carbon dioxide or a CO2-equivalent total. The “(e)” — carbon dioxide equivalent — matters at an earlier step, not this one. It signals that non-CO2 gases (methane, nitrous oxide, refrigerants) have already been converted into their CO2-warming equivalent using a global warming potential factor. That GWP step is where the science lives; the kg→tonne step is pure arithmetic applied afterward. If you still need to turn a mass of one gas into CO2e, do the GWP conversion first, then bring the result here.
Related converters and calculators
Once your figures are on a tonnes basis, the next step is usually a full inventory: the Scope 1–2–3 GHG inventory aggregator rolls activity data up into a reported total, and the Scope 1 combustion calculator is a common source of the kilogram figures you will convert. For a mass total that is still in a single gas, start from a GWP converter to reach CO2e before scaling the units here.
Frequently Asked Questions
Exactly 1,000. The metric tonne is defined as 1,000 kilograms, so 1 tonne CO2e = 1,000 kg CO2e. To go from kilograms to tonnes, divide by 1,000; to go back, multiply by 1,000.
Not always. In GHG accounting “tonne” means the metric tonne (1,000 kg), which is the reporting standard. A US short ton is 907.18 kg and a UK long ton is 1,016.05 kg — both differ from the metric tonne, so convert those to metric tonnes before using this page.
No. Dividing a mass by 1,000 to get tonnes does not depend on which gas the mass represents. The “(e)” only records that non-CO2 gases were already converted to a CO2-equivalent using their global warming potential — a separate, earlier step from the unit conversion.
Organisational footprints run to thousands or millions of kilograms, so tonnes keep the headline numbers readable and comparable. The GHG Protocol, DEFRA/DESNZ factors, CDP and ISO 14064-1 all standardise on tonnes of CO2e (tCO2e) for the reported total.
Divide by 1,000,000 (a million), because there are 1,000 grams in a kilogram and 1,000 kilograms in a tonne. It is often clearest to convert grams to kilograms first (÷1,000), then kilograms to tonnes (÷1,000) using this page.