What Is Volumetric Weight?
Volumetric weight explained, including the L x W x H / 6000 formula used for air freight, with a worked illustrative example.
On this page
- 01How It Works — The Formula
- 02Why 6000? Understanding the Divisor as a Density Threshold
- 03Example (Illustrative Only)
- 04Volumetric Weight and Chargeable Weight
- 05Volumetric Weight Does Not Apply to Sea Freight the Same Way
- 06Calculating Volumetric Weight for Multi-Piece Shipments
- 07A Second Worked Example: Multiple Pieces of Different Sizes
- 08How Packaging Choices Change Volumetric Weight
- 09Confirming the Right Divisor Before Booking
- 10Quick Reference
Quick Answer
Volumetric weight (also called dimensional weight) is a calculated weight based on a shipment's dimensions rather than its actual mass, used by carriers — particularly in air freight — to account for cargo that's bulky but light. For air freight, the standard formula is: volumetric weight (kg) = (length x width x height, in centimeters) / 6000, where 6000 is a commonly used industry divisor, equivalent to treating 1 CBM as roughly 167 kg. This figure is then compared against the shipment's actual weight, with the higher of the two used as the chargeable weight for pricing. Volumetric weight matters most for cargo with a lot of empty internal space or lightweight, bulky packaging — and it is a completely different calculation from the CBM-based weight-or-measure logic used in sea freight.
Key Takeaways
- Volumetric weight is calculated from a shipment's dimensions, not its actual weight.
- The standard air freight formula is (L x W x H in cm) / 6000.
- The 6000 divisor is equivalent to a density threshold of roughly 167 kg per cubic metre.
- Volumetric weight is compared against actual weight, and the higher figure becomes the chargeable weight.
- Bulky, lightweight cargo is the case most affected by volumetric weight calculations.
- Sea freight does not use the 6000 divisor at all — CBM-based W/M pricing runs on a different ratio entirely.
Volumetric weight, also called dimensional weight, is a way of expressing how much space a shipment occupies as if it were a weight figure. It exists because cargo space on aircraft (and to a lesser extent, other transport modes) is limited by volume as well as by weight capacity — a large, light shipment can take up as much usable space as a much heavier, denser one, so carriers need a way to price for that space. Understanding how this number is built — not just what the final figure is — makes it possible to anticipate air freight costs before a quote arrives, and to spot when a packaging choice is quietly inflating what a shipment will cost to move.
Key points at a glance
Volumetric weight is calculated from a shipment's dimensions, not its actual weight.
The standard air freight formula is (L x W x H in cm) / 6000.
The 6000 divisor is equivalent to a density threshold of about 167 kg per cubic metre — cargo lighter than that is volume-driven.
Volumetric weight is compared against actual weight, and the higher figure becomes the chargeable weight.
The 6000 divisor is an air freight convention — it is not the ratio used for sea freight CBM pricing.
How It Works — The Formula
For air freight, volumetric weight is calculated as: Volumetric weight (kg) = (Length × Width × Height, in cm) ÷ 6000. 6000 is a widely used industry-standard divisor for general air cargo, expressed as cubic centimetres per kilogram. This is the same divisor used as the default in this site's chargeable weight calculator. Some carriers or trade lanes may use a different divisor (such as 5000, common for courier and parcel-level shipments) for specific cargo types or service levels, so it's worth confirming the exact factor for a given shipment — but 6000 is the standard reference point for planning general air cargo.
Volumetric weight formula
Volumetric weight (kg) = (L cm × W cm × H cm) ÷ 6000
- L, W, H
- Length, width, height of the piece, in centimetres
- 6000
- IATA-referenced divisor for general air cargo (cm³ per kg)
- Equivalent CBM ratio
- ≈ 167 kg per 1 CBM
Why 6000? Understanding the Divisor as a Density Threshold
The number 6000 isn't arbitrary — it encodes a density threshold. Dividing by 6000 cm³/kg is mathematically the same as saying: if a shipment's density is below roughly 167 kg per cubic metre, its volumetric weight will exceed its actual weight, and volume becomes the pricing basis. If density is above that threshold, actual weight stays the higher figure. This is a useful mental shortcut: instead of running the full formula for every shipment, a rough sense of whether cargo is denser or lighter than water-in-a-box-shaped terms (167 kg/m³ is roughly one-sixth the density of water) predicts which side of the comparison it will land on. Dense products — metal parts, liquids in rigid containers, machinery — are almost always actual-weight cargo. Bulky, airy products — foam, textiles, assembled furniture, packaging materials — are almost always volumetric-weight cargo.
Example (Illustrative Only)
Suppose a carton measures 60 x 50 x 40 cm and weighs 18 kg actual. Volumetric weight = (60 x 50 x 40) / 6000 = 120,000 / 6000 = 20 kg. Comparing the two figures: actual weight is 18 kg, volumetric weight is 20 kg. Since 20 kg is greater than 18 kg, the chargeable weight used for pricing would be 20 kg. This example uses clearly hypothetical numbers for illustration only — always use real cargo dimensions and weight, and confirm the applicable divisor, when planning an actual shipment.
Volumetric Weight and Chargeable Weight
Volumetric weight is not, by itself, the number that ends up on an invoice — it's one of two inputs into chargeable weight, which is the figure actually billed. Once volumetric weight is calculated, it's compared against actual weight, and the greater of the two becomes chargeable weight, conventionally rounded up to the next 0.5 kg for air freight. It's a common shorthand to say a shipment was "charged on volumetric weight", which really means its volumetric figure won that comparison and became the chargeable weight. The full mechanics of that comparison, the rounding convention, and worked multi-piece examples are covered in "What Is Chargeable Weight?"
Volumetric Weight Does Not Apply to Sea Freight the Same Way
It's tempting to assume the same dimensional logic carries over to sea freight, but it doesn't — sea freight, particularly LCL, is priced on CBM directly, compared against weight on a weight-or-measure (W/M) basis using roughly 1 CBM ≈ 1,000 kg, not the air freight divisor of 6000 (≈167 kg per CBM). These are two different ratios built for two different physical realities: aircraft hold space is scarcer and more expensive per cubic metre than a ship's hold, which is part of why the air-freight threshold treats cargo as volume-driven at a much lower density than sea freight does. Never take a volumetric weight calculated with the 6000 divisor and use it to estimate a sea freight quote — it will be off by a factor of roughly six. Full detail on the sea-freight side is in "What Is CBM (Cubic Meter) in Shipping?"
Calculating Volumetric Weight for Multi-Piece Shipments
When a shipment has more than one piece, volumetric weight should be calculated per piece and then summed, rather than estimated from a single "representative" box. For pieces of the same size, calculate the volumetric weight of one and multiply by quantity. For a shipment with several different box sizes, calculate each size's volumetric weight separately, multiply each by its own quantity, and add every result together — the same line-by-line discipline used for CBM calculations. Skipping this and averaging box sizes, or using only the largest piece as a stand-in for the whole shipment, tends to understate the true total when a shipment has many medium-sized bulky pieces rather than one dominant large one.
Three cargo profiles compared
| Profile | Actual weight (60x50x40cm box) | Which figure wins |
|---|---|---|
| Dense (e.g. metal hardware) | 28 kg | Actual weight (28 kg > 20 kg volumetric) |
| Balanced | 20 kg | Equal — either figure gives the same result |
| Bulky (e.g. textiles, foam) | 9 kg | Volumetric weight (20 kg > 9 kg actual) |
A Second Worked Example: Multiple Pieces of Different Sizes
Consider a shipment made up of three distinct package lines rather than a single uniform box. Line 1 is 4 cartons at 55 x 45 x 35 cm, actual weight 6 kg each. Line 2 is 2 cartons at 80 x 60 x 50 cm, actual weight 22 kg each. Line 3 is 1 crate at 100 x 80 x 70 cm, actual weight 45 kg.
Volumetric weight per line: Line 1 — (55 x 45 x 35) / 6000 = 86,625 / 6000 ≈ 14.44 kg per carton, x 4 = 57.75 kg. Line 2 — (80 x 60 x 50) / 6000 = 240,000 / 6000 = 40 kg per carton, x 2 = 80 kg. Line 3 — (100 x 80 x 70) / 6000 = 560,000 / 6000 ≈ 93.33 kg, x 1 = 93.33 kg.
Total volumetric weight: 57.75 + 80 + 93.33 ≈ 231.08 kg. Total actual weight: (6 x 4) + (22 x 2) + 45 = 24 + 44 + 45 = 113 kg. Since total volumetric weight (≈231.08 kg) is greater than total actual weight (113 kg), the shipment's chargeable weight would be based on the volumetric figure, rounded up to the next 0.5 kg per the standard air freight convention — in this case 231.5 kg. Notice that no single line dominates this result; it's the sum across all three lines that determines the outcome, which is exactly why line-by-line calculation, not a rough estimate from the largest piece, is the reliable method.
Actual vs volumetric weight in the multi-piece example
Actual weight (total)
113 kg
Volumetric weight (total)
231.08 kg
Chargeable weight (rounded)
231.5 kg
From the second worked example above: 3 package lines (4 cartons 55x45x35 cm, 2 cartons 80x60x50 cm, 1 crate 100x80x70 cm) with combined actual weight 113 kg and combined volumetric weight approximately 231.08 kg, rounded up to a 231.5 kg chargeable weight per the standard air freight convention. Illustrative figures only, not a live rate calculation.
How Packaging Choices Change Volumetric Weight
Because volumetric weight is calculated from outer dimensions, packaging decisions have a direct and often underappreciated effect on it. A box with a lot of unused internal space — oversized for the product it contains, or padded with bulky filler material — inflates volumetric weight without adding any actual protective value beyond what a properly sized box would provide. Right-sizing cartons to the product, using compression packaging where the product allows it, and choosing protective materials that don't add unnecessary bulk are the most direct ways to bring a shipment's volumetric weight closer to its actual weight, and in doing so reduce the odds — and the extent — of being priced on the volumetric figure at all.
Confirming the Right Divisor Before Booking
Because the divisor is what turns dimensions into a weight figure, using the wrong one changes the outcome directly. Before relying on a self-calculated volumetric weight for planning purposes, confirm with the specific carrier or forwarder which divisor applies to that shipment and service level — 6000 for general air cargo is a reliable default assumption, but courier and parcel services commonly apply a lower divisor such as 5000, and some specialised cargo categories may use other figures entirely. A quick confirmation before booking avoids planning around a number that turns out not to match what actually appears on the invoice.
Quick Reference
A short list to keep close at hand.
- Formula: volumetric weight (kg) = (L × W × H in cm) ÷ 6000.
- The 6000 divisor is equivalent to a density threshold of roughly 167 kg per cubic metre.
- Compare against actual weight; the higher figure becomes chargeable weight (rounded up to 0.5 kg for air freight).
- For multi-piece shipments, calculate per piece and sum — don't average or use only the largest piece.
- This formula and divisor apply to air freight only — sea freight uses a completely different CBM-based ratio.
Common Mistakes
- Using the wrong unit (e.g. mm or inches) directly in the formula without converting to centimeters first.
- Assuming a shipment will be billed on actual weight without checking whether volumetric weight is higher.
- Using an outdated or wrong divisor for a specific carrier or trade lane instead of confirming the applicable one.
- Applying the air freight 6000 divisor to a sea freight shipment, instead of the CBM-based W/M ratio sea freight actually uses.
What You Need to Prepare
- Length, width and height of each piece, measured on its actual outer packaging.
- Actual gross weight of the shipment, to compare against the calculated volumetric weight.
- Confirmation of the divisor the specific carrier or service level applies.
Frequently Asked Questions
What is the formula for volumetric weight in air freight?
Volumetric weight (kg) = (Length x Width x Height, in centimeters) / 6000, where 6000 is a commonly used industry-standard divisor for general air cargo. Always convert dimensions to centimeters first if a shipment was measured in millimeters or inches, since the formula assumes centimeter inputs.
Is the volumetric divisor always 6000?
6000 is a widely used industry-standard divisor for general air cargo, but some carriers or trade lanes — especially courier and parcel services — use a different figure, such as 5000. It's worth confirming the applicable divisor for a specific shipment.
Does volumetric weight apply to sea freight too?
No — volumetric weight using the 6000 divisor is specific to air freight. Sea freight, particularly LCL, uses CBM (cubic meters) directly as the basis for pricing, compared against weight on a weight-or-measure basis using a different ratio (roughly 1 CBM ≈ 1,000 kg, not 167 kg).
Why does the 6000 divisor equal roughly 167 kg per CBM?
1 CBM equals 1,000,000 cubic centimetres. Dividing 1,000,000 by the 6000 divisor gives approximately 166.7 kg — so a shipment with exactly 1 CBM of volume has a volumetric weight of roughly 167 kg under the standard air freight formula.
How can I reduce a shipment's volumetric weight?
Right-sizing cartons to the product, avoiding excess internal empty space, and using compact rather than bulky protective packaging all reduce the outer dimensions the calculation is based on — which lowers volumetric weight for cargo where it's currently the higher, and therefore chargeable, figure.
Should I calculate volumetric weight per piece or for the whole shipment at once?
Per piece, then summed. Calculating volumetric weight from a single overall bounding box for a multi-piece shipment, or from only the largest piece, tends to misstate the true total — the reliable method is to calculate each distinct piece or package line separately and add the results together.