How to calculate truck CO2e

Road freight emissions under the GLEC Framework v3.3 and ISO 14083 are the cargo's tonnes, times the distance, times an emission intensity per tonne-kilometre. How good the number is depends on the data you have: a fleet average, your own load, or your own fuel.

The formula

Emissions (kg CO2e) = cargo (t) × distance (km) × intensity (g CO2e per tonne-km) ÷ 1,000

Report it well-to-wheel (WTW): the diesel burnt (tank-to-wheel, TTW) plus producing and delivering it (well-to-tank, WTT).

Step 1: the distance

Route the trip on the road network: that's the shortest feasible distance (SFD). Trucks drive a bit further (detours, finding the address), so GLEC's road default values include +5% and are used with the SFD as it is. An intensity per tonne-km actually driven, such as UK DESNZ's, needs the distance adjustment factor (GLEC Section 1, Chapter 4): the SFD × 1.05.

Step 2: the intensity

Without data of your own, use a default value for the truck type at an average load. GLEC Framework v3.3, Europe, articulated truck 34–40 t, average load (60% loaded, 17% empty running), diesel: 78 g TTW + 23 g WTT = 101 g CO2e per tonne-km. GLEC has separate tables for North America, China and India, and an uplift for Asia and Africa.

Worked example: 20 t from Hamburg to Munich

Step	Value
Routed road distance (OpenStreetMap)	776 km
Tonne-km: 20 t × 776 km (GLEC's value includes the 5%)	15,526 tkm
Tank-to-wheel: 15,526 × 78 g	1,211 kg CO2e
Well-to-tank: 15,526 × 23 g	357 kg CO2e
Well-to-wheel	1,568 kg CO2e

Calculated live on Sootcase, October 2026.

Better data, a better number

ISO 14083 prefers primary data (measured fuel) over modelled data (a model of your operation) over default data (published averages).

Your own load. If you know the truck carries 20 t and drives 0.2 km empty for every loaded km, a load model (UK DESNZ 2026, articulated truck over 33 t) gives 77.78 g CO2e per tonne-km for the same trip, × 1.05 as DESNZ's values are per km driven: 1,268 kg instead of 1,568, 19% less, because this truck is fuller than the average.
Your own fuel. Best of all: the litres of diesel the trip used, times the fuel's emission factor, shared between the shipments on the truck by tonne-km.

One thing to watch: in DESNZ's load model, "100% laden" is an average full load (17.9 t for an articulated truck over 33 t), not the truck's legal payload. If you know the tonnes on the truck, give the tonnes.

What this doesn't include

Depots and cross-docks: a separate hub operation in ISO 14083, added on top.
Refrigeration: use a refrigerated truck factor for chilled or frozen goods.

Calculate a truck shipment · See which shipments could go by rail · What a truck trip pays for carbon and tolls · How Sootcase calculates