How do you calculate chargeable weight for air freight?

Why does volume matter in air freight?

Chargeable weight is not always the number on the scale. Aircraft space is limited, and a shipment of large, light cartons can use the same amount of aircraft space as a much heavier shipment.

For example, a shipment of pillows may weigh little but occupy a lot of room. If airlines charged only by actual kilograms, they could fill an aircraft with bulky, low-weight cargo and earn too little for the space used. Volume weight converts occupied space into a billable weight.

A dense shipment usually bills on actual weight. A light but bulky shipment usually bills on volume weight.

How do you calculate volume weight?

For standard international air cargo, use centimeters and kilograms. Multiply each piece's length, width and height, multiply by the number of pieces, then divide by 6,000.

Volume weight (kg) = L × W × H (cm) × pieces ÷ 6,000

Chargeable weight = the higher of actual gross weight and volume weight

• Measure each piece in centimeters.
• Multiply length, width, height and quantity.
• Divide by the applicable divisor.
• Compare the result with the total actual gross weight.
• Use the higher figure as the chargeable weight.

The 6,000 divisor is the common IATA-based standard for scheduled air cargo.

Which divisor should you use?

Never assume every quote uses 6,000. A smaller divisor produces a larger volume weight, so the same cartons can price differently on a standard air freight rate and an express courier rate.

The pricing person should confirm the divisor from the airline, consolidator, courier tariff or rate confirmation before quoting. Do not copy a volume weight from an old quote without checking the current service and rate basis.

How should you round chargeable weight?

In these examples, chargeable weight is rounded up to the next 0.5 kg. Always follow the airline, consolidator, or courier's published rounding rule.

• 47.0 kg stays 47.0 kg
• 47.1 kg becomes 47.5 kg
• 47.5 kg stays 47.5 kg
• 47.6 kg becomes 48.0 kg
• 83.26 kg becomes 83.5 kg

Do not round down. A rate quote may be based on a half-kilo increment, whole kilograms, or a carrier-specific rule. The chargeable weight in your quote should follow the rule on the buying rate, then be carried consistently into the selling quote.

Example: when actual weight wins

Dense cargo bills on its actual weight. Two crates of machinery parts weigh far more than the space they take up.

• Shipment: machinery parts, 2 crates
• Dimensions per crate: 60 × 50 × 40 cm
• Actual weight per crate: 85 kg, so 170 kg in total

Volume: 60 × 50 × 40 × 2 = 240,000 cm³. Volume weight: 240,000 ÷ 6,000 = 40 kg.

This shipment is dense. It weighs much more than its volume equivalent, so actual weight wins.

At 170 kg it falls in the +100 kg band. At a +100 rate of $3.55 per kg, the air freight is 170 × $3.55 = $603.50.

Example: when volume weight wins

Light, bulky cargo bills on its volume weight. Four cartons of retail displays weigh 72 kg but take up the space of 200 kg.

• Shipment: retail display materials, 4 cartons
• Dimensions per carton: 100 × 60 × 50 cm
• Actual weight per carton: 18 kg, so 72 kg in total

Volume: 100 × 60 × 50 × 4 = 1,200,000 cm³. Volume weight: 1,200,000 ÷ 6,000 = 200 kg.

The cartons are light for their size, so the shipment bills at 200 kg, not 72 kg. At the +100 rate of $3.55 per kg: 200 × $3.55 = $710.00.

If the same shipment moved through a courier using the 5,000 divisor, it would bill at 1,200,000 ÷ 5,000 = 240 kg, before the courier's own rounding and rating rules. That is why the divisor must be checked before you quote.

How do you handle a mixed shipment?

Calculate the volume of each piece type, multiply by its quantity, then add all the volume together before dividing by the divisor. Do not assume every piece in a shipment has the same dimensions.

A mixed shipment may have cartons, crates, pallets or loose pieces with different sizes and densities.

• Actual gross weight: (3 × 12) + (2 × 35) + (1 × 180) = 286 kg
• Carton A: 3 × 60 × 40 × 40 = 288,000 cm³
• Carton B: 2 × 120 × 80 × 60 = 1,152,000 cm³
• Crate C: 1 × 150 × 100 × 90 = 1,350,000 cm³
• Total volume: 2,790,000 cm³
• Volume weight: 2,790,000 ÷ 6,000 = 465 kg

Because volume weight is higher, quote the shipment at 465 kg, subject to the airline or consolidator's final acceptance and remeasurement.

How is non-stackable air cargo rated?

Non-stackable freight needs special attention in air cargo because the airline is selling usable aircraft space, not just kilograms. If a pallet cannot be safely stacked, the carrier or handling agent may rate the space above it as occupied, or apply a non-stackable adjustment based on the airline's build-up and acceptance rules.

The key point is that a non-stackable pallet does not automatically receive an LCL-style "non-stackable CBM" charge. Air freight is still normally rated on actual or volume weight, unless the airline specifically confirms a non-stackable uplift, minimum footprint, or chargeable-weight adjustment.

When a pallet cannot safely support cargo on top, the airline or handling terminal may place a non-stackable cone above it. The cone identifies the pallet as non-stackable and signals that cargo must not be loaded on top during build-up. If the airline includes the cone in the rating height, add the confirmed cone height to the pallet's accepted overall height before calculating volume weight.

Example: A pallet measures 120 × 100 × 110 cm and weighs 150 kg. The airline requires a 50 cm non-stackable cone. The rating height becomes 160 cm, so the volume weight is 120 × 100 × 160 ÷ 6,000 = 320 kg, rather than 120 × 100 × 110 ÷ 6,000 = 220 kg. Compare 320 kg with the actual gross weight of 150 kg and use the higher figure. The chargeable weight is 320 kg.

Do not add a cone height unless the airline, ground handler, or consolidator confirms that it applies and confirms the height to use. Some carriers may instead apply a non-stackable surcharge, a fixed assumed height, positional weight, or refuse the freight if it cannot be safely built into the planned aircraft position.

At acceptance, the warehouse may reweigh and remeasure the cargo, confirm whether it can be stacked, and revise the chargeable weight. If the final accepted weight or dimensions are higher than quoted, the airline cost changes and the forwarder must address the difference.

What is a common non-stackable quoting mistake?

A common quoting mistake is when a salesperson or pricing executive sees "non-stackable" and applies an LCL-style non-stackable calculation to an air shipment without checking the airline's actual rule. That can make the quote far too expensive, especially for a short pallet that is light but cannot be stacked.

The customer compares it with another forwarder's normal air freight quote, sees a large difference, and the quote is lost before anyone explains why.

The correct approach is to ask the airline or consolidator: is there a confirmed non-stackable charge, how is it calculated, and does it apply to this exact pallet size, height, route, and service? Quote the confirmed airline basis, not an assumption carried over from ocean LCL practice.

What is the weight-break check?

Before applying a rate, check whether billing the shipment at the next weight break is cheaper. This is a pricing-desk habit that saves money every time a shipment sits close to a higher break.

Air freight rates often use breaks such as:

• Minimum charge
• Normal rate, for shipments under 45 kg
• +45 kg
• +100 kg
• +300 kg
• +500 kg
• +1,000 kg

The per-kilo rate usually drops as the weight break increases. That means a shipment below a break can sometimes cost less if billed at the next break.

Example: a 90 kg chargeable-weight shipment

Although the shipment weighs 90 kg, charging it at the 100 kg break costs $23 less. So do not automatically apply the 90 kg chargeable weight at the +45 rate. Compare the two:

• Current-band cost = chargeable weight × current-band rate
• Next-break cost = next break weight × next break rate

With these rates the crossover is 84.52 kg ($355 ÷ $4.20). Rounded to the half kilo, any shipment of 85 kg or more is cheaper billed as 100 kg at the +100 rate.

If the higher break is cheaper, use it only when the carrier, consolidator or rate sheet permits that rating method. Record it clearly in the buy rate and selling calculation.

How do you calculate it in inches and pounds?

For U.S. shippers who give dimensions in inches and weight in pounds, divide cubic inches by 166 for standard air cargo, or by 139 for couriers. Do not convert every shipment to metric if the airline or courier rate is already quoted in pounds.

• Standard air cargo: volume weight (lb) = L × W × H (in) × pieces ÷ 166
• Courier: dimensional weight (lb) = L × W × H (in) × pieces ÷ 139
• Per-kilo rates: volume weight (kg) = L × W × H (in) × pieces ÷ 366

166 and 139 are common conversions for pricing in pounds. The actual divisor comes from the airline, consolidator or courier tariff.

U.S. example

• Shipment: 3 cartons
• Dimensions per carton: 24 × 18 × 16 inches
• Actual weight per carton: 22 lb, so 66 lb in total

Total cubic inches: 24 × 18 × 16 × 3 = 20,736 in³. Standard air volume weight: 20,736 ÷ 166 = 124.92 lb, which becomes 125 lb under whole-pound rounding.

If the rate is per kilogram: 20,736 ÷ 366 = 56.66 kg, rounded up to 57.0 kg. The actual weight of 66 lb is 29.9 kg, so volume weight still wins.

If the same cartons move through a courier using ÷139: 20,736 ÷ 139 = 149.18 lb, which becomes 150 lb if the courier rounds to the next whole pound.

Same cartons. Same actual weight. Different service. Different divisor. Different billable weight.

What should you check before sending an air freight quote?

Before sending an air freight quote, confirm each of these.

• Actual gross weight, and whether it includes packaging, pallets, skids or crates
• Exact dimensions of every piece, in the carrier's measurement unit
• Number of pieces at each dimension
• Whether any piece is non-stackable, and the airline's confirmed basis for rating it
• Whether the shipment is standard air cargo, courier, express or a consolidator service
• The divisor required by the buying rate: 6,000, 5,000, 166, 139 or another stated factor
• The carrier's rounding rule
• Actual weight versus volume weight, using the higher result
• The applicable minimum charge and each nearby weight break
• Whether billing at the next break is cheaper and permitted
• Any special commodity, dangerous goods, oversize, security, handling or terminal charges

Chargeable weight is one of the easiest places to lose margin in air freight. A quotation can look correct because the rate per kilogram is correct, while the wrong divisor, wrong rounding rule, missed pallet dimensions or missed weight break quietly makes the cost wrong. Standardize the calculation, record the basis, and keep the rate source with the quote.