Freight CO₂e following the GLEC Framework and ISO 14083
Freight emission calculators often disagree, by a factor of two or more for the same shipment. Two academic studies ran the same shipments through several well-known calculators. Below are their published results, with Carbonara's for the same inputs added. All figures are kg or tonnes CO₂e, well-to-wheel.
Schramm & Lehner (2024), "Innovators and transformers: a benchmarking study of online carbon emission calculators for freight transport", International Journal of Physical Distribution & Logistics Management 54(11), Table 1. Calculators run in May 2023 with their default settings. Each mode on its own.
| Calculator | Road | Rail | Sea | Air |
|---|---|---|---|---|
| CarbonCare | 5,335 | 1,227 | 712 | 47,582 |
| DHL | 6,282 | 2,885 | 1,549 | 66,201 |
| NTMCalc | 8,754 | 1,615 | 1,065 | 53,420 |
| EcoTransIT World | 7,970 | 3,930 | 1,280 | 67,800 |
| GEODIS | 10,526 | 3,299 | 1,024 | 67,803 |
| LogWARD | 12,271 | 3,155 | 1,661 | 72,275 |
| Carbonara | 10,084 | 3,425 | 1,600 | 56,938 |
Carbonara is inside the range of the six for every mode, on the higher side for road, rail and sea, and below most for air because it leaves out radiative forcing, as ISO 14083 does. Its routed distances are within 2–5% of the study's average (road 10,467 km, rail 10,461 km, sea 20,016 km before the GLEC sea adjustment of 15%, air 8,543 km). Inputs: a 40 t articulated truck at average load, a freight train, a container ship (EU MRV deep-sea factor), a freight aircraft.
Olivari, Caballini & Lluch (2025), "How to calculate GHG emissions in freight transport? A review of the main existing online tools", Case Studies on Transport Policy 19, 101343, Figures 5 and 9 (values read from the chart labels). A semitrailer with 16 t, diesel Euro 5, 60% load, 30% empty running. Tonnes CO₂e for the whole chain.
| Case | GLEC | GreenRouter | EcoTransIT | TK'Blue | Route Scanner | Carbonara |
|---|---|---|---|---|---|---|
| A1 road, rail, road | 1.22 | 0.85 | 0.67 | 0.76 | – | 1.20 |
| A2 road, RoRo ship, road | 1.46 | 1.72 | 1.34 | 1.28 | – | 1.41 |
| A3 road, RoPax ferry, road | 3.06 | 3.78 | – | 2.84 | – | 5.74 |
| A4 all road | 1.47 | 1.42 | 1.48 | 1.18 | – | 1.74 |
| B road, container ship to Singapore | 1.58 | 2.19 | 1.69 | 1.33 | 1.61 | 1.80 |
A1 and A2 are within 3% of the GLEC reference, and B is within the range of the five tools. Two cases are not, and we say so: the RoPax ferry (A3) uses the UK government's (DESNZ) RoPax factor, which is about twice what GLEC gives for this crossing; and the all-road case (A4) is 18% above GLEC, partly because the study doesn't publish its distances. Carbonara was given the truck's load as 16 t (load_tonnes), which is what the study's "60% of a semitrailer" means.
Every Carbonara result shows how it was calculated, step by step, with the GLEC Framework page and ISO 14083 clause behind each step, so you can redo it by hand. Open the calculator Read the methodology
The other calculators' results are the studies' published figures; we did not rerun them. Carbonara's results are for the inputs described, on this service in October 2026, and will change when its emission factors are updated. Carbonara is not certified; results are calculations following GLEC v3.2 and ISO 14083.