# Carton volume (CBM) and freight per unit

Add mixed carton sizes, gross weight and units, estimate container space and air chargeable weight, and allocate freight to each product and unit.

Sources checked 2026-10-22. https://storecalc.com/en/cbm/

This shipment is 3.420 CBM and 560 kg, less than half of a 20GP's usable space, so compare LCL (shared container) quotes first; ocean freight averages $0.17/unit, highest for Hoodies at $0.45.

Volume and weight estimate only, not a packing guarantee. Placement, doors, pallets, stacking and road weight limits are not modeled. Confirm equipment and price when booking.

## How it works

Row CBM = length × width × height (cm) × cartons ÷ 1,000,000. 1 in = 2.54 cm; 1 lb = 0.45359237 kg.
Row gross weight = gross weight/carton × cartons; units = units/carton × cartons.
DIM kg = CBM × 1,000,000 ÷ divisor. The default 6000 is common for air freight; use 5000 or your quoted divisor as needed. Shipment billing takes the higher of total gross and total DIM; per-carton billing sums each carton's higher weight. Carrier rounding is not applied.
Freight = CBM × rate, pricing weight × rate, or a flat quote. Ocean kg pricing uses gross weight; air uses chargeable weight. CBM pricing does not automatically apply W/M (weight or measure, whichever is greater).
Product allocation = shipment freight × product volume (or gross weight) ÷ shipment total for that basis. Freight/unit = product allocation ÷ product units. Calculations use unrounded values; displayed cents may have rounding differences.
Theoretical minimum containers = round up max(total CBM ÷ planned usable CBM, gross kg ÷ example payload). This does not solve carton placement or guarantee loading.

## Worked example

These carton sizes, quantities, weights and $120/CBM are StoreCalc worked-example inputs, not industry standards or live freight rates. Measure outside dimensions and include packaging in gross weight.

| Product name | cm | kg/Carton size | Cartons | Units/carton | CBM | kg | Total units | USD | USD/Freight per unit |
|---|---|---:|---:|---:|---:|---:|---:|---:|---:|
| T-shirts | 60 × 40 × 40 | 18 | 20 | 100 | 1.920 | 360.00 | 2000 | 230.40 | 0.12 |
| Hoodies | 60 × 50 × 50 | 20 | 10 | 40 | 1.500 | 200.00 | 400 | 180.00 | 0.45 |

Air volumetric weight: 570.00 kg; Air chargeable weight: 570.00 kg; Shipment freight: $410.40.

[Use 2400 units and $410.40 freight to calculate landed cost](../landed/?q=2400&fr=410.40&mode=ocean&qt=fob)

The shipment link carries only quantity and freight. Different products need their own purchase prices and duty rates; use the per-product links for a mixed shipment.

## Container volume estimate

Common container types, using Hapag-Lloyd example equipment, not a universal carrier specification. Planned usable volume = nominal capacity × your utilization setting. Payload excludes the empty container's weight.

85% is an example allowance for gaps, not a carrier standard. Set it from your packing plan.

| Container to view | Nominal CBM | Planned usable CBM | Example payload (kg) | Theoretical minimum containers |
|---|---:|---:|---:|---:|
| 20GP | 33.2 | 28.22 | 28130 | 1 |
| 40GP | 67.7 | 57.55 | 28750 | 1 |
| 40HQ | 76.3 | 64.86 | 28600 | 1 |

## Questions

### How do I calculate CBM?

Multiply outside length, width and height in centimeters by carton count, then divide by 1,000,000. Calculate each carton size separately and add the results.

### How are ocean and air shipments billed?

This page supports ocean CBM or gross-kg quotes, air chargeable-kg quotes and flat prices. Actual LCL quotes may use W/M, minimums and surcharges. FCL is usually priced per container; enter that as a flat quote.

### What changes between divisors 6000 and 5000?

For the same volume, divisor 5000 gives 20% more DIM weight than 6000. DHL Global Forwarding illustrates 6000 for air freight; the DHL Express China 2026 guide uses 5000 per piece. Confirm the billing scope separately from the divisor.

### Why allocate bulky goods by volume?

When the quote is volume-driven, bulky goods use space even if they weigh little. Volume allocation assigns that cost to the space used. Choose gross weight when weight drives your quote. This is a cost allocation choice, not a carrier rule.

### Does one container mean it will fit?

No. Only volume and weight are compared. Long cartons, small doors, stacking limits, pallet gaps and road limits can invalidate the estimate. The default 85% is an adjustable example assumption.

### What if carton data or unit counts are incomplete?

Blank, negative, or fractional carton/unit counts prompt you to complete inputs and pause freight and container estimates. A rate of 0 means free freight; 0 cartons excludes a row.

## Have an AI assistant check it

Please check the freight allocation for this shipment. Figures from StoreCalc https://storecalc.com/en/cbm/; sources checked 2026-10-22.
Inputs (dimension unit cm, weight unit kg):
[{"name": "T-shirts", "l": 60, "w": 40, "h": 40, "kg": 18, "n": 20, "u": 100}, {"name": "Hoodies", "l": 60, "w": 50, "h": 50, "kg": 20, "n": 10, "u": 40}]
Transport Ocean, quote basis Price per CBM, USD quote 120, allocation by Volume; DIM divisor 6000, billing basis Higher of shipment gross or DIM.
This shipment is 3.420 CBM and 560 kg, less than half of a 20GP's usable space, so compare LCL (shared container) quotes first; ocean freight averages $0.17/unit, highest for Hoodies at $0.45.
Check for missing minimum charges, W/M terms, rounding, port charges, pallets or delivery. Explain packing limitations. Do not treat the estimate as a booking guarantee or invent rates.

## Sources and scope

Sources checked: 2026-10-22
- [Hapag-Lloyd 20GP](https://www.hapag-lloyd.com/en/services-information/cargo-fleet/container/20-standard.html)
- [Hapag-Lloyd 40GP](https://www.hapag-lloyd.com/en/services-information/cargo-fleet/container/40-standard.html)
- [Hapag-Lloyd 40HQ](https://www.hapag-lloyd.com/en/services-information/cargo-fleet/container/40-standard-high-cube.html)
- [DHL Global Forwarding: chargeable weight](https://www.dhl.com/gb-en/home/global-forwarding/freight-forwarding-education-center/calculating-chargeable-weights.html)
- [DHL Express China 2026, p. 15](https://mydhlplus.dhl.com/content/dam/downloads/cn/en/rate-guide/service_and_rate_guide_cn_en_2026.pdf.coredownload.pdf)