Convert t CO₂/TJ to kg CO₂/GJ
This is the pair of units the IPCC and national inventories use for fuel emission factors — and they are numerically identical. A terajoule is 1,000 gigajoules and a tonne is 1,000 kilograms, so the two thousands cancel: t CO₂/TJ = kg CO₂/GJ, no arithmetic needed. Both also equal g CO₂/MJ. The converter confirms the identity and lets you carry a value between the labels with confidence.
t CO₂/TJ and kg CO₂/GJ are the same number — the conversion factor is 1. So 56.1 t CO₂/TJ = 56.1 kg CO₂/GJ = 56.1 g CO₂/MJ. The value only changes when you move to a different unit family, such as per kWh (× 3.6) or the kg CO₂/TJ that IPCC tables often use (× 1,000).
kg CO₂/GJ = t CO₂/TJ × 1. The ratio is exactly one because 1 t / 1 TJ = 1,000 kg / 1,000 GJ = 1 kg/GJ. The identity holds for CO₂, CO₂e or any single gas, and for any per-energy intensity — not just emission factors.
One number, four labels
The reason these units cause confusion is that the same carbon intensity can be written four ways that all look different. Here is a single value — the IPCC default for natural gas — in each:
| Unit | Natural gas | Relation |
|---|---|---|
| kg CO₂/TJ | 56,100 | as published in IPCC tables |
| t CO₂/TJ | 56.1 | ÷ 1,000 (kg → t) |
| kg CO₂/GJ | 56.1 | = t CO₂/TJ (identical) |
| g CO₂/MJ | 56.1 | = kg CO₂/GJ (identical) |
| g CO₂/kWh | 202 | × 3.6 (per MJ → per kWh) |
The IPCC 2006 Guidelines publish default CO₂ factors in kg CO₂/TJ — natural gas is 56,100, not 56.1. That is 1,000× the t CO₂/TJ figure. If you read a five-figure number straight into a spreadsheet expecting t/TJ or kg/GJ, every result is a thousand times too big. Always check whether an IPCC-sourced factor is in kg/TJ or t/TJ before using it.
IPCC default factors across the units
The IPCC 2006 default CO₂ emission factors for common fuels, shown in the forms you will meet them in. The middle column — t CO₂/TJ, equal to kg CO₂/GJ and g CO₂/MJ — is the value this converter carries:
| Fuel | kg CO₂/TJ (IPCC) | t/TJ = kg/GJ = g/MJ | g CO₂/kWh |
|---|---|---|---|
| Natural gas | 56,100 | 56.1 | 202 |
| LPG | 63,100 | 63.1 | 227 |
| Motor gasoline | 69,300 | 69.3 | 249 |
| Diesel / gas oil | 74,100 | 74.1 | 267 |
| Fuel oil | 77,400 | 77.4 | 279 |
| Hard coal | 94,600 | 94.6 | 341 |
IPCC 2006 default CO₂ factors, net calorific value basis. To move the right-hand columns between per-MJ and per-kWh, use the g CO₂/MJ to g CO₂/kWh converter (× 3.6).
t CO₂/TJ to kg CO₂/GJ conversion table
Because the factor is 1, the two columns match exactly — the table is really a reassurance that no hidden scaling is happening.
| t CO₂/TJ | kg CO₂/GJ |
|---|---|
| 1 | 1 |
| 56.1 | 56.1 |
| 74.1 | 74.1 |
| 94.6 | 94.6 |
| 100 | 100 |
Where these units are used
- National greenhouse-gas inventories. Energy statistics are compiled in terajoules and petajoules, so inventory emission factors are applied per TJ — the IPCC 2006 Guidelines are the standard source.
- IPCC default factors. The IPCC publishes its default combustion CO₂ factors in kg CO₂/TJ; converting to t/TJ (or the identical kg/GJ) is often the first step in using them.
- Cross-checking against per-kWh or per-litre factors. Utility and DEFRA-style factors are per kWh or per litre, so an inventory factor per TJ has to be brought onto a common energy basis before the two can be compared.
- Estimating combustion emissions. The factor multiplies fuel energy to give CO₂; the stationary combustion calculator does the full estimate, while this converter just aligns the factor’s units.
Frequently Asked Questions
You don’t need to — they are the same number. A terajoule is 1,000 gigajoules and a tonne is 1,000 kilograms, so the two thousands cancel and the factor is 1. So 56.1 t CO₂/TJ = 56.1 kg CO₂/GJ.
Yes. Each step up the energy unit (MJ → GJ → TJ) multiplies by 1,000, and each step up the mass unit (g → kg → t) multiplies by 1,000, so they cancel at every level. A fuel at 56.1 in any of these three units is 56.1 in the others.
Because the IPCC publishes default factors in kg CO₂/TJ, and 56,100 kg/TJ = 56.1 t/TJ = 56.1 kg/GJ. It is a 1,000× difference in the label only. Reading a kg/TJ figure as if it were t/TJ or kg/GJ is a common and large error.
Multiply the g CO₂/MJ value (equal to t/TJ and kg/GJ) by 3.6, because 1 kWh = 3.6 MJ. So natural gas at 56.1 g/MJ is about 202 g CO₂/kWh. Use the g CO₂/MJ to g CO₂/kWh converter for that step.
The unit identity itself is exact and basis-independent, but the underlying factor values depend on whether the energy is net or gross calorific value. When comparing factors, make sure they share the same NCV or GCV basis as well as the same units.
No. The unit identity is about mass per energy, so it is the same for CO₂, CO₂e or any single gas. CO₂e just means non-CO₂ combustion gases (a little CH₄ and N₂O) have been folded in using their global warming potentials before the factor is stated.