For a standard air-freight estimate, calculate the packed shipment's actual gross weight and volumetric weight. The chargeable weight is normally the greater of the two. A common air-freight divisor is 6,000 cm³ per kg; an express-courier service may use 5,000 instead. Confirm the service rule, rounding and minimum charge in the written quote before treating the number as final.
Why quoted kilograms can exceed scale weight
An importer can receive a quote based on more kilograms than the goods weigh on a scale. That is not necessarily an error: an aircraft has both weight and space limits, and a large, light consignment occupies capacity. The useful question is which service is quoted, what is included in the packed measurements, and how the billable unit is calculated.
Start with the shipment as it will leave the supplier or packing warehouse. A product's net weight and dimensions are useful for purchasing, but the transport calculation needs the final cartons, protective packaging and any pallets. If the supplier repacks the goods, the earlier measurements may no longer describe the shipment being booked.
Actual, volumetric and chargeable weight
Actual gross weight is the weight of the cargo as presented for transport, including its packaging and, where applicable, pallets. Volumetric weight converts the outer packed dimensions into a weight-equivalent number. Chargeable weight is the billing basis after the applicable comparison and service rules are applied.
For a commonly used standard air-freight calculation, divide the total packed volume in cubic centimetres by 6,000, then compare it with gross weight. If volume is supplied in cubic metres, the same divisor gives approximately 166.7 kg per CBM. This is a calculation convention, not a universal tariff or a price per kilogram. Carrier and product rules must still be confirmed.
Volumetric weight (kg) = packed volume (cm³) ÷ 6,000
Chargeable weight (kg) = greater of gross weight or volumetric weight
Worked example: why 800 kg can still be billed differently
Assume a China-origin shipment has a gross weight of 800 kg and a packed volume of 3.2 CBM. At the common 6,000 air-freight divisor, its volumetric weight is approximately 533.3 kg: 3.2 × 1,000,000 ÷ 6,000. The larger figure is the actual gross weight, so the unrounded calculation basis is 800 kg.
Now keep the gross weight at 800 kg but increase the final packed volume to 5.4 CBM. Volumetric weight becomes 900 kg. The unrounded calculation basis becomes 900 kg, even though the physical weight did not change. The final billable weight may still depend on the service's rounding, minimum and measurement rules.
This example explains a weight basis, not a transport price. Applying a guessed USD/kg rate would still miss the lane, service level and agreed scope. Pickup, handling, customs work and destination delivery should be checked separately in the customer quote rather than assumed to be included in a headline freight rate.
| Shipment / gross weight | Packed volume | Volumetric weight | Chargeable basis |
|---|---|---|---|
| A: 800 kg | 3.2 CBM | About 533.3 kg | 800 kg |
| B: 800 kg | 5.4 CBM | 900 kg | 900 kg |
Why an express parcel can produce another number
For express courier, do not silently reuse the air-freight divisor. DHL Express's published example uses length × width × height in centimetres divided by 5,000, calculated for each piece, then compares dimensional and actual weight. Other services can differ.
Suppose the same 3.2 CBM / 800 kg totals are considered under a hypothetical service using a 5,000 divisor. The aggregate dimensional calculation is 640 kg, so gross weight would still be higher. But that does not mean a parcel quote can be inferred by simply substituting 5,000 into an air-freight calculation. Package-level comparison, rounding, acceptance limits and service fees can change the final quote.
For mixed carton sizes, request a package-level packing list rather than one approximate shipment volume. A change in carton dimensions, void space or pallet height can change the result without changing the product quantity. For a pallet shipment, record the final outside dimensions and gross weight after wrapping and protection are complete.
Five checks before comparing quotes
Use the same packed cargo data and delivery requirement when asking providers to quote. Otherwise, a difference in the displayed kilograms or starting price may reflect different assumptions rather than a comparable service.
- Confirm the product. Is the quote standard air freight, a consolidation service or international express? Ask which divisor and measurement method apply.
- Use final outer dimensions. Record each packed carton or pallet as it will be tendered, including protective packaging. Mark estimated measurements as provisional.
- Check both weights. Provide actual gross weight and package dimensions. Ask whether the provider compares weights per piece or on the shipment aggregate, and how fractions are rounded.
- Define the full service scope. State pickup location, destination, cargo-ready date, delivery point, Incoterm, commodity and any special handling. A chargeable-weight result alone is not a delivered price.
- Confirm acceptance and exceptions. Batteries, dangerous goods, oversized packages or other controlled cargo may need product-specific approval, documentation and a different service. Do not infer acceptance from a calculator result.
What to check in a customer freight quote
A customer freight quote should identify the proposed service, the cargo information used and the charges included in the agreed scope. Chargeable weight is one pricing input; it does not, by itself, determine the price you will pay. Check the currency, quote validity and whether pickup, export handling, main carriage, customs coordination and final delivery are included.
Treat an indicative starting price as a planning reference. Ask for a written, route-specific quote that confirms the final packed measurements, billable weight and service terms before booking. Duties, taxes and any excluded destination or special-handling charges should be identified so you can compare the same delivery outcome.
FREQUENTLY ASKED QUESTIONS
Questions to ask before booking.
Is air freight always charged on actual weight?
No. A common rule compares actual gross weight with volumetric weight and uses the larger figure. The divisor, rounding and minimum charges depend on the quoted product, so confirm them in the written service quote.
Does 1 CBM always equal 167 kg?
No. Approximately 166.7 kg per CBM follows from a 6,000 cm³/kg divisor. A 5,000 convention equates to 200 kg per CBM before package-level rules. Other products can use different ratios.
If my carton measurements change, should I request another quote?
Yes, if the final packed dimensions, weight or package count materially change. Send revised data before booking so the provider can check the billable basis, acceptance and related service charges.
Can chargeable weight tell me the final freight price?
No. It is only one pricing input. The rate, route, chargeable-weight rules, surcharges and service scope must be confirmed in the customer freight quote.
Sources and further reading
These sources support the planning context. Product-specific customs, tax and regulatory requirements should be confirmed with the appropriate qualified adviser.