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Freight Cost Calculator: Splitting Ocean, Air and Express Cost Across Your Order

Start with shipment records

Build the calculator around each shipment, not one total for the whole order. For every shipment, record:

  • product and order references;
  • mode and service: air, ocean LCL, ocean FCL, rail, road or express;
  • carrier and quoted freight charge;
  • number of packages;
  • each package’s length, width and height in centimetres;
  • each package’s gross weight in kilograms, including packaging and pallets;
  • the carrier-confirmed density ratio or divisor;
  • the agreed allocation basis for products; and
  • who is responsible for freight under the agreed commercial terms.

The calculator determines the weight used for comparison. The carrier’s quote supplies the monetary charge. Do not derive a rate per kilogram or cubic centimetre unless the carrier has provided one for that shipment.

Apply the “whichever is greater” rule

DHL Global Forwarding explains that carriers of air, ocean, road and rail freight compare two measurements: actual gross weight and volumetric weight. Actual gross weight is the physical weight of the shipment, including packaging and pallets. Volumetric weight converts the space occupied by the packages into a comparable weight using a density ratio.

The calculation is:

Actual weight = sum of the gross weights of all packages

Volumetric weight = sum of (package length × width × height ÷ density divisor)

Chargeable weight = the greater of actual weight and volumetric weight

For identical packages, the volumetric calculation can be written as:

(length × width × height ÷ divisor) × number of packages

This matters for light but bulky goods. Their actual weight may be low while their volumetric weight is high. A calculator that checks actual weight alone will therefore understate the carrier’s billing weight.

Retain the unrounded inputs and results. If the carrier gives a calculation or rounding instruction, record it beside the result rather than applying an unexplained convention.

Use the divisor for the quoted mode

The evidence provides these calculation bases:

  • Air freight: divide centimetres by 6,000. Maersk gives the same formula and describes 6,000 as an industry standard set by the International Air Transport Association (IATA). This is Maersk’s account; it is not a citation to an IATA publication.
  • Ocean LCL freight: divide centimetres by 1,000.
  • Rail freight: divide centimetres by 3,000.
  • Road freight: calculate the divisor case by case. DHL Global Forwarding states that road density ratios vary by location and carrier, so obtain the basis from the intended carrier.
  • Ocean FCL freight: do not apply the LCL volumetric calculation to create the charge. DHL states that a per-container charge replaces the LCL volume-based charge.

Record the divisor against the individual carrier quote. Do not assume that a ratio familiar from one lane or shipment will be accepted for another.

Work the two-package example through every mode

Use DHL’s example: two packages, each measuring 120 × 80 × 50 cm.

First calculate the volume of one package:

120 × 80 × 50 = 480,000 cm³

Air freight

Using the air divisor:

480,000 ÷ 6,000 = 80 kg per package

80 × 2 = 160 kg volumetric weight

The shipment’s air chargeable weight is therefore:

max(actual gross weight of both packages, 160 kg)

Ocean LCL freight

Using the LCL divisor:

480,000 ÷ 1,000 = 480 kg per package

480 × 2 = 960 kg volumetric weight

The shipment’s LCL chargeable weight is:

max(actual gross weight of both packages, 960 kg)

Rail freight

Using the rail divisor:

480,000 ÷ 3,000 = 160 kg per package

160 × 2 = 320 kg volumetric weight

The shipment’s rail chargeable weight is:

max(actual gross weight of both packages, 320 kg)

Road freight

Do not insert a road divisor from memory. Obtain the carrier’s density ratio for the location and shipment, write it in the calculator record, and then calculate the volumetric result using that confirmed basis.

The worked example supplies dimensions but not the actual gross weight of the two packages. Enter their recorded gross weights before producing a final chargeable-weight figure. Do not treat a dimensional result as the final figure until it has been compared with actual weight.

Handle FCL and changing density ratios separately

For an FCL shipment, enter the carrier’s per-container quote rather than allocating 960 kg or another LCL dimensional result as the freight basis. If several products share the container, you still need an internal product-allocation key, but that key is separate from the carrier’s volume-based LCL calculation.

DHL also warns that density ratios can differ between carriers and shipments. Its example uses the same shipment with a 1:3 ratio and a 1:2 ratio: volumetric weight changes from 333.33 kg to 500 kg. That is the budgeted weight changing even though the shipment itself has not changed.

Therefore, save the ratio used in each calculation. When a carrier confirms a different ratio, recalculate before comparing quotes or approving the budget. The monetary effect then follows the carrier’s quoted charging basis.

Keep express outside the volumetric step

Treat express as a separate lane in the calculator and do not assume it follows the air rule. Record the shipment’s actual gross weight and its dimensions, then obtain and record the charging basis the carrier actually applies to that express lane. Do not apply the air volumetric divisor unless the carrier confirms it for that lane, and do not present the air volumetric step as express billing without that confirmation.

This separation prevents an air-freight calculation from being carried into an express quotation merely because the shipment may travel by air.

Split the confirmed freight across products and shipments

Splitting is where most calculators go wrong: the arithmetic is easy and the allocation rule is where two buyers get different totals from the same quote. Decide the splitting basis once, then apply it.

Map each product quantity to its package and shipment first. Then calculate each shipment once; do not repeat the combined package dimensions as a new shipment for every product.

For each shipment, record:

  1. its actual weight;
  2. its volumetric weight, where applicable;
  3. its chargeable weight;
  4. the confirmed freight charge; and
  5. the product-allocation key.

If the parties agree to split a shipment charge by weight, use:

Product allocation = shipment freight charge × product allocation weight ÷ total product allocation weight

For a product shipped in several shipments, add its allocation from each shipment:

Total product freight = the sum of that product’s shipment allocations

Name the chosen allocation key in the RFQ or contract. Do not call it carrier chargeable weight unless the product portions reconcile to the shipment’s calculated chargeable weight. For FCL, state the separate basis used to divide the per-container charge.

DHL notes that shippers who underestimate chargeable weight risk an unpleasant surprise when the bill arrives. A missing dimension, incorrect divisor or assumed density ratio can cause the calculated billing weight to be lower than the carrier’s assessment.

Write these headings into the RFQ or quote sheet

Use the following clause headings and retain the stated evidence with each response.

Shipment and package data

Require the supplier to list every shipment, package count, package dimensions in centimetres and package gross weight in kilograms, including packaging and pallets.

Evidence to retain: completed package schedule. DHL defines actual weight as including packaging and pallets.

Mode and chargeable-weight basis

Require the carrier or supplier to identify air, ocean LCL, ocean FCL, rail, road or express, and state the density ratio or divisor used. Road responses must provide the carrier-confirmed basis. FCL responses must identify the per-container charge.

Evidence to retain: carrier calculation or written quotation showing the basis used.

Freight cost responsibility

State the applicable Incoterms® 2020 rule and confirm separately who pays the freight and whether it is included in the product price.

Evidence to retain: the agreed commercial term and written cost allocation. The International Chamber of Commerce states that Incoterms® 2020 provides clear allocation of cost, risk and obligations.

Product allocation method

Name the allocation key, identify the products and shipments covered, and state how allocations across multiple shipments are combined.

Evidence to retain: the package-to-product map and completed allocation schedule.

Assumption changes

Require the carrier-confirmed density ratio or divisor to be recorded for each shipment and recalculated if it differs from the original assumption.

Evidence to retain: the original basis and any confirmed revision.

Express basis

Identify express as its own lane, record actual gross weight and dimensions, and state the charging basis the carrier confirmed for that lane. Record explicitly whether the air volumetric divisor was confirmed, not applied, or still unknown.

Evidence to retain: express quote identifying its charging basis.

The finished calculator should therefore show, for every shipment, the inputs, formula, divisor, actual and volumetric results, final billing basis and quoted charge. A separate product summary should show each shipment allocation and the total assigned to each product. Any road ratio, FCL container charge, express basis or cost-responsibility assumption should remain visible rather than being buried in the total.

Only when that allocation exists does a freight number become comparable across suppliers. Add the allocated freight to the goods cost in the quote comparison tool so a delivered-cost ranking is not decided by one supplier quoting factory gate and another quoting delivered. Common error: ranking quotes on unit price alone and finding the freight difference only when the invoices arrive.

Source context

Each claim below is supported by the cited page. The workflow, headings and worked arithmetic above are Suppliers Help editorial guidance, not text from these sources. Sources checked 2026-10-02.