How is volumetric weight (desi) calculated? The formula

What volumetric weight is, and why it is calculated

Volumetric weight is the weight-equivalent of the space a shipment occupies. The carrier compares the gross weight measured on the scale with the volumetric weight. The higher figure is treated as the chargeable weight, and freight is billed on that figure.

The reasoning is a capacity constraint. An aircraft, truck or container faces two limits at once: the maximum tonnage it can carry and the maximum volume that fits inside it. A shipment full of styrofoam does not strain the vehicle’s tonnage but occupies half the hold. If charged only on scale weight, the carrier would be carrying that volume for free. Volumetric weight reduces these two constraints to a single measure.

Same formula, different divisor

The basic formula is the same in every mode:

Width (cm) × Length (cm) × Height (cm) ÷ Divisor = Volumetric weight (kg)

The only thing that changes is the divisor. The divisor determines how many kilograms the carrier counts per 1 m³.

Mode	Conversion	Equivalent of 1 m³	Threshold density
Air freight (IATA)	cm³ ÷ 6,000	≈ 167 kg	167 kg/m³
International express courier	cm³ ÷ 5,000	200 kg	200 kg/m³
Domestic parcel (desi)	cm³ ÷ 3,000	333 desi	333 kg/m³
Road groupage (m³-based)	m³ × ~333 kg	~333 kg	depends on carrier
Road groupage (ldm-based)	ldm × ~1,750 kg	—	depends on carrier
Sea LCL (w/m)	1 m³ = 1,000 kg	1,000 kg	1,000 kg/m³

The air freight (6,000) and international express (5,000) divisors are widely used standards; charter or special contracts, and some couriers’ domestic products, may apply different ratios. The conversions in the road and sea rows, however, vary by route, carrier and contract; when getting a quote, the applied factor should be confirmed in writing.

The “threshold density” column is the most practically useful piece of information: if the shipment’s density (kg ÷ m³) is below the threshold, volumetric weight is billed; if above, gross weight is billed.

Step-by-step example calculation

A single-pallet shipment. Dimensions are taken including the pallet and stretch wrap.

• Dimensions: 120 × 80 × 100 cm
• Gross weight: 85 kg

Step 1 — Find the volume. 120 × 80 × 100 = 960,000 cm³ = 0.96 m³

Step 2 — Divide by the mode’s divisor.

• Air freight: 960,000 ÷ 6,000 = 160 kg
• International express: 960,000 ÷ 5,000 = 192 kg
• Domestic parcel: 960,000 ÷ 3,000 = 320 desi

Step 3 — Compare with gross weight. In air freight: 85 kg gross versus 160 kg volumetric weight.

Step 4 — Bill the higher figure. In air freight, the chargeable weight is 160 kg. The same pallet is priced at 192 kg by international express and at 320 desi by domestic parcel. The cargo never changed; only the divisor did.

Ldm in road freight: by floor space or by weight?

Ldm (loading metre) is the full-width, 1-metre slice of the trailer along its length; by industry convention a width of 2.40 m is used, so 1 ldm = 1 m × 2.40 m = 2.40 m² of floor area (the actual interior width is usually about 2.45 m). In the example, the pallet’s footprint is 1.20 × 0.80 = 0.96 m²; dividing this area by 2.40 m² gives 0.4 ldm.

• By the ldm method: 0.4 × 1,750 ≈ 700 kg
• By the m³ method: 0.96 × 333 ≈ 320 kg

The two methods give results that differ by a factor of about 2.2 for the same load. This is the most common reason road-groupage quotes look impossible to compare. In addition, the ldm calculation assumes the full height is being used; some carriers reduce the ratio for low pallets, others do not.

Desi and the sea LCL logic

Desi is the unit used in Türkiye for domestic parcel and e-commerce pricing: 1 desi = 3,000 cm³. Parcel carriers take whichever is higher between desi and kilograms and tier their price lists in desi ranges. Desi is a domestic convention; applying that same 3,000 divisor to an international shipment is a frequent mistake.

Sea LCL works on a w/m (weight or measurement) logic instead of volumetric weight: 1 m³ is compared with 1,000 kg, and the higher is counted as the “freight ton.” Since the pallet in the example is 0.96 m³ and 0.085 tons, the calculation gives 0.96 freight ton; however, because most LCL tariffs carry a minimum of 1 m³ / 1 ton, the invoice is in practice issued on 1 freight ton. Under FCL, volumetric weight is not calculated at all; the price is per container, and the limit is the container’s maximum payload capacity.

What to watch for when measuring

• Measurements are taken from the outer edges of the load: pallet feet, stretch film, corner boards, lids, tape and any parts overhanging the pallet are included.
• Height is measured from the floor to the highest point. A standard EUR pallet alone adds 14.4 cm.
• If there is a hanging label, a protruding carton flap or a projecting fitting, measurement is taken accordingly; the terminal measures the same way.
• Measurements are in centimetres and are generally rounded up. In air freight, chargeable weight is often rounded up to the next 0.5 kg.
• For multi-piece shipments, each package’s volume is measured separately. In air freight and LCL, total volumetric weight is compared with total gross weight; in domestic parcel, most carriers price each package separately on its own desi. Which method applies should be confirmed in the quote.
• If the load cannot be stacked, this must be declared upfront. Otherwise the carrier may count the height as the vehicle’s full interior height or apply a multiplier.

Why shrinking the packaging works better than cutting weight

Volume is the product of three dimensions, so a reduction in size has a cubic, not linear, effect. If 5 cm is trimmed off each dimension of the example pallet, it becomes 115 × 75 × 95 = 819,375 cm³, and the air freight volumetric weight drops from 160 kg to roughly 136.6 kg. A saving of roughly 15%, from removing just a handful of empty space.

By contrast, removing 5 kg of actual weight from the same shipment changes the bill not at all, since the chargeable weight is already coming from volume. Cutting kilograms while density stays below the threshold is wasted effort.

Practical levers: sizing boxes to the product to reduce filler space, using nesting packaging, packing the product flat, consolidating two half-pallets into one, and rebuilding the stacking plan. But the limit on shrinking packaging is damage risk; the volume gained must outweigh the increased damage and insurance cost.

Common mistakes

• Calculating from the product’s dimensions. If packaging, pallet, stretch wrap and overhangs are not included, the invoice gets corrected after re-measurement at the terminal.
• Memorising a single divisor. 3,000 is for domestic parcel. Air freight uses 6,000, international express uses 5,000.
• Not asking which method a road quote uses. The same pallet can come out to 700 kg by ldm or 320 kg by m³.
• Rounding dimensions down or declaring them as “approximate.” The difference comes back later as an additional invoice.
• Not stating the stacking status. A “cannot be stacked” note added afterward can double the volume.
• Taking one box in a multi-piece shipment as representative of the whole batch.
• Overlooking the minimum charge item. The 1 m³ / 1 ton minimum in LCL, and the minimum charge in air freight, changes the outcome.
• Confusing volumetric weight with customs value. In Türkiye, the customs value on import is found, under Customs Law No. 4458, by adding freight and insurance up to the point of entry into Türkiye to the transaction price (even if the delivery term is FOB or EXW). The VAT base on import is then calculated by adding customs duty and other charges to this value. Volumetric weight, by increasing freight, therefore affects the tax indirectly.

The effect of dimension and divisor choice on price is seen most in groupage shipments; pallet arrangement and consolidation options are also part of this calculation.