Calculate transport emissions for China imports
Calculate each transport leg separately: multiply shipment tonnes by kilometres travelled, then by the matching emissions factor. Add the legs and document factor choices, estimates and exclusions. Ask Cambridge China Bridge to help gather factory dispatch and shipment records.
Define the journey you are measuring
Start your calculation at the agreed factory dispatch point and finish at receipt at your UK warehouse. Map collection, consolidation transfers, the international journey and UK delivery. Include transhipment legs rather than treating the shipment as a direct journey. Our shipping guide explains the transport arrangements.
Write a boundary note before calculating. State whether terminal handling, temporary storage, refrigeration and empty equipment movements are included, excluded or unmeasured. Keep product manufacture and subsequent customer deliveries outside this particular total, and name those exclusions. This produces a defined transport estimate rather than a claim about the product’s entire footprint.
Collect shipment activity data
Ask the factory and forwarder for shipment references, dispatch and receipt dates, actual cargo mass, packing details, collection and delivery addresses, ports or airports, intermediate stops and transport modes. Retain packing lists, transport documents and delivery records alongside the calculation.
Record distance separately for each leg, with its source. Ask for the booked route or carrier distance; label any route estimate. Use actual transported cargo mass for a mass-based calculation, checking how the chosen factor treats packaging. Keep volumetric or chargeable weight separate: a freight billing measurement is not automatically the activity measurement your emissions factor needs.
Match the factor to the freight mode
Use the DESNZ full-set workbook for the reporting year you are assessing, and read the relevant worksheet guidance before selecting a row. For outsourced transport, start with the freighting-goods worksheet. Record the exact row, unit and assumptions. For commercial trade-offs alongside the emissions comparison, see sea versus air freight.
| Transport leg | What to establish |
|---|---|
| Road collection or delivery | Vehicle class, fuel, loading assumption and whether the factor uses vehicle distance or tonne-kilometres |
| Sea freight | Container ship or other vessel category, cargo mass and sailing route |
| Air freight | Flight category, transfer airports, distance treatment and whether radiative forcing is included |
| Rail freight | Applicable rail factor and whether its geographical assumptions suit the route |
| Courier shipment | Underlying road and air legs, or a carrier calculation with an explicit boundary |
Calculate without mixing units
For a tonne-kilometre factor, multiply cargo mass in tonnes by leg distance in kilometres. Multiply that activity by the matching factor to obtain the leg’s emissions. Sum the legs in a consistent carbon dioxide equivalent unit. A vehicle-distance factor instead needs vehicle kilometres and an explicit allocation to your consignment.
For shared loads, record how any carrier total was allocated to your goods. Do not assign the whole vehicle’s emissions to every consignment or allocate an already shipment-specific result again. Ask whether fuel supply emissions are included before adding a separate upstream calculation. For air freight, record the distance uplift and radiative-forcing treatment, checking that adjustments are not applied again.
Keep a calculation someone can reproduce
Save the workbook version, selected factors, original activity records, unit conversions, allocation method and boundary note. DESNZ says users should report their emissions-accounting methods. Flag missing legs and estimated inputs visibly; do not present an incomplete route as a complete factory-to-warehouse total.
Ask the forwarder to explain any difference between its reported total and your calculation before combining them. Compare shipment options using the same boundary and assumptions. Keep emissions allocation separate from freight cost allocation, since the basis used to divide a bill may differ from the basis used to estimate emissions.
Frequently asked questions
Can I calculate freight emissions from the invoice?
Use the invoice to identify the shipment, then obtain cargo mass, route distances and modes. A freight charge alone does not provide the activity data for a tonne-kilometre calculation.
Should I use actual or chargeable weight?
For a mass-based freight calculation, use actual transported cargo mass and check the factor’s packaging treatment. Keep chargeable weight as a separate billing field.
Do I include transport within China?
Include factory collection and other Chinese transport legs when your stated boundary starts at the factory. If those records are missing, label the gap or estimate rather than silently omitting it.
Can I use UK factors for the whole route?
Check each factor’s geographical and operating assumptions. Record any use as a proxy for a Chinese leg, explain the limitation and seek carrier data where available.