How to calculate CO2 emissions for road freight
To calculate CO2 emissions for road freight, multiply shipment weight in tonnes by distance in km by an ISO 14083 emission factor.
Logifie Team
Logistics Technology Experts
To calculate CO2 emissions for a road freight shipment, multiply the shipment weight in tonnes by the distance in kilometres, then multiply by an emission factor in kg CO2e per tonne-km. Under ISO 14083:2023 and the GLEC Framework, a diesel articulated truck (34-40 tonnes) uses a factor of around 0.101 kg CO2e per tonne-km.
What is the formula for calculating road freight CO2 emissions?
The calculation has three inputs: shipment weight, distance travelled, and an emission factor for the vehicle and fuel type. Multiply weight in tonnes by distance in kilometres to get tonne-kilometres, then multiply by the emission factor to get total CO2e for the leg. A 20-tonne shipment moved 500 km by a diesel articulated truck at 0.101 kg CO2e per tonne-km produces roughly 1,010 kg, just over one tonne, of CO2e. A TMS that already logs consignment weight, route distance, and vehicle type removes most of the manual work, capturing the data the formula needs at booking rather than reconstructing it later from delivery notes.
Which emission factor should you use for a diesel truck?
Emission factors vary by vehicle class, load factor, and fuel type, so 0.101 kg CO2e per tonne-km for a fully loaded 34-40t diesel articulated truck is a representative default, not a universal constant. A rigid truck under 12 tonnes, an LCV, or a part-loaded trailer carries a higher factor per tonne-km as load factor drops, since the vehicle burns close to the same fuel whether full or half-empty. The GLEC Framework, maintained by the Smart Freight Centre as the methodology behind ISO 14083:2023 , publishes default factor tables by vehicle segment for shippers without primary fuel-consumption data. Actual fuel burn from the carrier is more accurate than any default factor.
How do ISO 14083 and the GLEC Framework standardise the calculation?
ISO 14083:2023 is the international standard for quantifying and reporting greenhouse gas emissions from transport chain operations, formalising the GLEC Framework methodology logistics providers already used. It superseded the earlier EN 16258 standard and now underpins how EU shippers and carriers report freight emissions under Corporate Sustainability Reporting Directive (CSRD) Scope 3 obligations, phased in for large EU companies starting fiscal year 2024. Real-time tracking data on the route actually driven improves distance-input accuracy, since planned and actual distance can differ on congested corridors or with detours. The Logifie blog covers related EU regulatory changes affecting road transport operators.
Frequently asked questions
Does the calculation change for a part-load (LTL) shipment versus a full truckload?
Yes. A part-load or LTL shipment allocates a share of the vehicle's total emissions to each consignment based on its weight relative to total payload, rather than applying the full-truck factor to a fraction of the cargo. This weight-based allocation is set out in the GLEC Framework and carried into ISO 14083:2023.
What is the difference between well-to-wheel and tank-to-wheel emissions?
Tank-to-wheel emissions cover only fuel combustion during the vehicle's operation, while well-to-wheel emissions add the upstream emissions from extracting, refining, and transporting the fuel. ISO 14083 and the GLEC Framework recommend well-to-wheel reporting where possible for a more complete carbon footprint picture.
Do empty return legs count toward a shipment's CO2 emissions?
Under most GLEC Framework and ISO 14083-aligned methodologies, empty return legs are allocated back to the loaded trips a carrier runs, typically as an adjustment to the load factor, rather than treated as a separate zero-cargo event. This avoids undercounting the true carbon cost of a one-direction route.
Can I calculate CO2 emissions without knowing the exact shipment weight?
A reasonable estimate is possible using a standard weight assumption for the cargo type or a declared dimensional weight, though accuracy drops compared with actual scaled weight. Where exact weight is unavailable, using the highest plausible estimate is the more conservative, audit-safe approach for CSRD-style reporting.
Get accurate weight, distance, and route data flowing into your emissions calculations automatically by connecting your fleet to a transport management system .
