Business Travel, Freight & Logistics Emission Factors — Complete Reference Dataset

This is the complete reference set of emission factors for moving people and goods — business air, rail, road and sea travel, multimodal freight, and delivery vehicles. It combines three authoritative sources: the UK Government’s DEFRA 2025 conversion factors (business travel and delivery vehicles, per passenger-km and per km), the GLEC Framework v3.2 (multimodal freight, per tonne-km), and the ICAO Carbon Emissions Calculator (aircraft fuel burn per flight). Every value is the frozen, citable snapshot carried in the MasterBrain (v2026.110 (2026-08-08)), verified cell-by-cell against the published source tables — with the well-to-tank/tank-to-wheel split, radiative-forcing basis, and per-source GWP vintage all made explicit.

What these factors are

Transport and logistics emissions appear across the whole GHG inventory: business travel is GHG Protocol Scope 3 Category 6; upstream and downstream freight are Categories 4 and 9; an operator’s own fleet is Scope 1. To turn activity data — passenger-kilometres flown, kilometres driven, tonne-kilometres shipped — into CO₂e, you multiply by an emission factor for the right mode, vehicle and fuel. This page is the complete, audit-grade reference for those factors.

Three measurement bases run through the dataset, and mixing them is the single most common error:

• Per passenger-km — people moving (air, rail, bus, ferry). The factor already divides the vehicle’s emissions across its passengers.
• Per km — a whole vehicle moving (a car, a van, an HGV). Used where you know distance travelled, not load carried.
• Per tonne-km — goods moving (all freight). The factor is the emissions to move one tonne one kilometre, after accounting for load factor and empty running.

Headline defaults at a glance

Sources, licence & GWP basis

This reference deliberately combines three complementary sources, each authoritative for its mode. They differ in unit, GWP vintage, and reuse licence — so each is labelled at the row level, and the table below states which is which.

Two further distinctions recur in every section. Well-to-tank (WTT) is the upstream emissions of producing and distributing the fuel; tank-to-wheel (TTW) is the combustion at the vehicle. DEFRA publishes both separately — the full figure is TTW + WTT (see §9). For aviation, radiative forcing (RF) uplifts the CO₂e to capture non-CO₂ high-altitude effects (contrails, NOₓ); DEFRA publishes air factors both with and without RF.

Radiative forcing: the aviation uplift

Business travel — air (per passenger-km)

DEFRA air factors are per passenger-km, split by haul band (domestic, short-haul, long-haul, international) and cabin class. The values below are “with radiative forcing” — the recommended basis; the without-RF and WTT figures are in the full dataset. Multiply by the great-circle distance flown × the number of passengers. See the business-travel air methodology for distance and uplift rules.

All values kg CO₂e per passenger-km, with radiative forcing, DEFRA 2025 ‘Business travel- air’. Cabin class scales the factor: business is ~2.9× economy, first ~4× (more floor space per passenger). Domestic is reported as a single average. Add WTT (e.g. long-haul economy +0.025) for the full life-cycle figure.

Business travel — rail, road, bus & taxi

Rail, bus, ferry and taxi are reported per passenger-km; cars, motorbikes and taxis (vehicle basis) are per km. Rail is among the lowest-carbon options; a car’s factor depends heavily on size and fuel. See the business-travel car methodology.

DEFRA 2025, AR5 GWP-100, tank-to-wheel. Car factors are per vehicle-km (not per passenger) — divide by occupancy for a per-person figure. The full dataset holds every segment (mini, supermini, lower/upper-medium, executive, luxury, sports, 4×4, MPV) and WTT companions.

Business travel — sea

Ferry passenger factors depend on whether the traveller brings a vehicle, which carries a share of the vessel’s load.

DEFRA 2025, AR5 GWP-100. A foot passenger’s footprint is ~7× lower than a car passenger’s — the vehicle dominates the allocation.

Aircraft fuel burn (ICAO, per flight)

For activity-based aviation accounting where the aircraft type and route are known, the ICAO Carbon Emissions Calculator publishes fuel burn per flight by equivalent aircraft code and stage length (great-circle distance band, in nautical miles). These are fuel mass figures, not CO₂e — convert with the jet-fuel factor (≈3.16 kg CO₂ per kg fuel). This is an ICAO source, included for completeness; it is not part of the DEFRA-OGL deposit.

All values kg fuel per flight. Source: ICAO Carbon Emissions Calculator v13, Appendix C. The full dataset carries every published equivalent aircraft code across all stage-length bands (125–3,500 nm).

Freight — multimodal intensities (per tonne-km)

Freight is measured per tonne-km on a well-to-wheel (WTW) basis, from the GLEC Framework v3.2 — the freight standard aligned with ISO 14083. Intensity falls sharply with vehicle size and load factor: a capesize bulk carrier moves a tonne for a fraction of the emissions of a small truck. GreenCalculus exposes these through the road, rail, sea and air freight calculators.

GLEC Framework v3.2, AR6 GWP-100, well-to-wheel. Road factors are region- and load-specific (the dataset holds China, EU/South America, India and North America sets); sea factors include a default 15% added for adverse weather (DAF). The full dataset carries every vessel class, container TEU-km factors, and the WTT/TTW split per row.

Delivery vehicles (per km)

For an operator’s own or contracted delivery fleet on a distance basis, DEFRA publishes per-km factors by vehicle type, weight band and laden percentage, with separate well-to-tank and SECR energy (kWh/km) companions. These drive the last-mile delivery and road freight calculators. Values below are average-laden, diesel, tank-to-wheel, with the WTT companion alongside.

DEFRA 2025, AR5 GWP-100. HGV factors scale with laden percentage: an all-HGV runs 0.660 at 0% laden, 0.836 at 50%, 1.012 at 100%. Refrigerated HGVs carry a transport-refrigeration-unit uplift. Battery-electric vans have zero tailpipe (TTW) emissions and a small WTT only. The full dataset holds every weight band × laden level × fuel, plus SECR kWh/km energy factors.

Well-to-tank vs tank-to-wheel

Every combustion factor has two parts. Tank-to-wheel (TTW) is what comes out of the exhaust. Well-to-tank (WTT) is the upstream emissions of extracting, refining and distributing the fuel before it reaches the tank. The complete life-cycle factor — what the GHG Protocol and SECR expect for Scope 3 completeness — is the sum.

Units & GWP basis

The dataset spans four activity units and two GWP vintages. Getting these right is the difference between an auditable inventory and a finding.

• Passenger-km (air, rail, bus, ferry passenger) — distance × passengers.
• Vehicle-km (cars, vans, HGVs on a distance basis) — distance only; divide by occupancy or load if you need a per-unit figure.
• Tonne-km (all freight) — tonnes × distance, already net of load factor and empty running.
• TEU-km (containerised sea freight) — per twenty-foot-equivalent-unit, an alternative to tonne-km for container moves.

GWP basis: DEFRA 2025 uses IPCC AR5 GWP-100 (CH₄ = 28, N₂O = 265), as required for UK SECR/UNFCCC reporting; GLEC v3.2 uses AR6. The two are within a few percent for these fuels but must not be silently mixed — see the IPCC AR6 GWP reference and the DEFRA fuel-factor dataset.

Application — formulas & worked examples

Each mode follows activity × emission factor (+ WTT), using the factor that matches the unit. Add the well-to-tank companion for a complete Scope 3 figure; include radiative forcing for air.

Framework requirements

Common reporting errors

1. Mixing activity units. Applying a per-passenger-km air factor to whole-flight distance, or a per-tonne-km freight factor to vehicle-km. The single largest transport-accounting error — always confirm the unit.
2. Omitting well-to-tank. Reporting only tailpipe (TTW) emissions understates the footprint by ~20–25% for road fuels. Scope 3 completeness requires WTT.
3. Dropping radiative forcing for air. Excluding RF understates aviation by ~70%. Disclose whether RF is included; most frameworks expect it.
4. Mixing AR5 and AR6. DEFRA travel/vehicle factors are AR5; GLEC freight is AR6. Combining them into one CO₂e total without disclosure is not reconcilable.
5. Using a vehicle-km car factor without occupancy. A car factor is per vehicle, not per person; a four-person trip should divide by occupancy for a per-traveller figure.
6. Ignoring cabin class for air. Business and first-class seats occupy several economy seats’ worth of space; using the economy factor for a business flight understates by 2–4×.
7. Treating freight load factor as 100%. GLEC intensities already embed realistic load factors and empty running; re-deriving from gross vehicle emissions double-discounts or overstates.
8. Stale vintage. DEFRA republishes annually; using a prior year’s workbook after the June refresh drifts from the mandated UK set.

Methodology, boundaries & uncertainty

Rounding & precision

Values are reproduced at the source precision — DEFRA factors to five decimal places, GLEC to the published intensity. Headline figures in prose are rounded for readability; the tables and the dataset carry the full precision.

GWP basis & boundary

DEFRA factors are AR5 GWP-100 (UK SECR/UNFCCC basis); GLEC freight is AR6. DEFRA road factors are tank-to-wheel with a separate well-to-tank companion; GLEC freight is well-to-wheel (TTW + WTT combined). Air factors are published with and without radiative forcing.

Licence scope of the deposited dataset

Only the DEFRA 2025 rows (business-travel passenger factors and delivery vehicles) are redistributed under the Open Government Licence v3.0 and carried in the citable DOI deposit. The GLEC Framework v3.2 and ICAO Carbon Emissions Calculator factors shown here are reproduced under fair citation for reference; cite Smart Freight Centre and ICAO directly for those values rather than redistributing them.

Uncertainty & applicability

These are average factors for fleet- and route-typical conditions. Real-world intensity varies with driving style, congestion, load, weather and route; primary data (actual fuel consumed, actual tonne-km) supersedes a default wherever available. DEFRA factors are UK-centric; GLEC road factors are region-specific.

Implementation & provenance chain

1. Primary sources — the DEFRA 2025 conversion-factor workbook, the GLEC Framework v3.2, and the ICAO Carbon Emissions Calculator v13, read at the tab/cell, table and appendix level. Each row records its source.cell_ref (e.g. 'Delivery vehicles'!P52).
2. MasterBrain rows — stored as canonical rows under business_travel.*, freight_detailed.* and delivery_vehicles.* with value, unit, gas, GWP set and cell reference. Version stamp: v2026.110 (2026-08-08).
3. REST API — exposed read-only at the public factors endpoint (§16).
4. CSV — flat machine-readable export.
5. Live calculators — the business-travel air, SECR, road/rail/sea/air freight and last-mile delivery calculators read these factors at runtime and emit an audit trail.
6. Update plan — DEFRA refreshes annually each June; GLEC and ICAO on their own cycles. Affected rows are updated in MasterBrain, the version increments, and the version history records the change.

Data access — REST API and CSV

The factor rows are available read-only. The citable DOI deposit covers the DEFRA-OGL subset; GLEC and ICAO rows are served for reference but cite their upstream owners.

REST API (JSON)

Query the live factors endpoint by section:

/wp-json/greencalculus/v1/factors?section=business_travel&limit=500
/wp-json/greencalculus/v1/factors?section=freight_detailed&limit=500
/wp-json/greencalculus/v1/factors?section=delivery_vehicles&limit=500

Open API endpoint →

Each row returns key, name, factor (value, unit, gas, GWP set), source (id, cell_ref) and scope.

CSV (flat dataset)

A flat CSV of the DEFRA business-travel and delivery-vehicle factors — key, value, unit, GWP basis, WTT companion, source cell — for direct import.

Cite this dataset

Cite each upstream source for its factors. The GreenCalculus compilation reference (DOI) covers the DEFRA-OGL subset and points to the machine-readable, version-stamped archive.

Frequently asked questions

Version history

Primary sources. DEFRA / DESNZ (2025) UK Government GHG Conversion Factors for Company Reporting 2025 (Open Government Licence v3.0); Smart Freight Centre (2023) GLEC Framework v3.2; ICAO Carbon Emissions Calculator Methodology v13. DEFRA material is reproduced under OGL v3.0; GLEC and ICAO values are cited for reference under their respective terms.

GreenCalculus implementation. MasterBrain v2026.110 (2026-08-08); values verified cell-by-cell against the DEFRA 2025 workbook tabs/cells, the GLEC v3.2 tables and the ICAO Appendix C by Jeremiah Say, June 2026. DEFRA factors reproduced at five-decimal precision; well-to-tank, tank-to-wheel and radiative-forcing variants retained and labelled.

Disclaimer. Published for reference and calculation. Average factors reflect fleet- and route-typical conditions; verify the units, GWP basis (AR5 vs AR6), WTT inclusion and radiative-forcing treatment required by your reporting framework, and use primary data where available, before finalising an inventory.

This dataset is published as part of MasterBrain — the GreenCalculus open emission-factor database, anchored to DEFRA, GLEC, ICAO, the IPCC and the GHG Protocol. Explore the DEFRA fuel-factor dataset →