Weight & volume
Volumetric weight
In one sentence
Volumetric weight converts a shipment's cube into kilogrammes using a ratio stated in the carrier tariff, so that a light but bulky consignment is billed on the space it fills rather than on what it weighs.
Overview
The calculation has two steps. Compute the volume in cubic metres — length × width × height, in metres, per item, summed — then multiply by the tariff ratio expressed in kilogrammes per cubic metre. A pallet of 1.20 × 0.80 × 1.60 m holds 1.536 m³; at a stated ratio of 250 kg/m³ its volumetric weight is 384 kg.
Parcel and air tariffs often express the same idea as a divisor in centimetres. IATA's volumetric standard for air cargo is 6,000 cm³ per kilogramme, which is the same thing as 167 kg/m³. Road groupage tariffs usually publish the kilogramme-per-cubic-metre form directly.
Volumetric weight is not automatically the billed weight: it is one candidate. The chargeable weight is the highest of the gross weight, the volumetric weight and, where the tariff defines one, the loading-metre equivalence. Cargavo is a TMS for freight brokers and stores the ratio on each carrier grid, so the same shipment can be priced correctly against several carriers at once.
How do you calculate volumetric weight?
Multiply length by width by height in metres to get cubic metres, then multiply by the ratio in the carrier tariff. Two pallets of 1.20 × 0.80 × 1.80 m give 3.456 m³; at 250 kg/m³ the volumetric weight is 864 kg.
Only two inputs matter, and both must be the loaded dimensions — pallet included, overhang included, shrink wrap included. Cargavo is a TMS for freight brokers and reads exactly the dimensions the quote form captured.
| Step | Operation | Example |
|---|---|---|
| Volume per item | L × W × H in metres | 1.20 × 0.80 × 1.80 = 1.728 m³ |
| Total volume | Sum over items | 2 items = 3.456 m³ |
| Volumetric weight | Volume × ratio | 3.456 × 250 = 864 kg |
If the tariff states a divisor in cm³/kg instead, convert once: 6,000 cm³/kg is 167 kg/m³, 5,000 cm³/kg is 200 kg/m³, 4,000 cm³/kg is 250 kg/m³. The two notations describe the same rule from opposite ends.
Why do carriers use different volumetric ratios?
The ratio expresses the density at which a vehicle fills its floor and its payload at the same time. Air freight, parcel networks and road groupage face different limits, so each publishes its own ratio — the tariff is the only authority.
A vehicle has two capacities, mass and space, and the ratio is where the carrier declares the exchange rate between them. Because the vehicles, the networks and the handling costs differ, so do the ratios.
- Air cargo — IATA's standard divisor of 6,000 cm³/kg, equivalent to 167 kg/m³.
- Parcel networks — a divisor set by the operator, published in its tariff conditions.
- Road groupage — a kilogramme-per-cubic-metre ratio, often paired with a loading-metre ratio for non-stackable freight.
The practical consequence is that a ratio is never a global setting. In a TMS for freight brokers, it belongs to the grid: Cargavo stores it per carrier grid so the same 3 m³ shipment can produce a different chargeable weight for two carriers, which is exactly what happens in reality.
When does volumetric weight beat the actual weight?
Whenever the shipment density falls below the tariff ratio. At 250 kg/m³, freight lighter than 250 kg per cubic metre is billed on volume. Divide gross weight by volume: below the ratio, volumetric weight wins and the quote must be built on it.
The break-even is one division, and it is worth doing before quoting rather than after invoicing. Cargavo is a TMS for freight brokers and performs it on every quote automatically.
| Shipment | Volume | Density | Billed on |
|---|---|---|---|
| 1,200 kg tiles | 1.6 m³ | 750 kg/m³ | Gross weight |
| 600 kg cartons | 3.0 m³ | 200 kg/m³ | Volumetric weight (750 kg) |
| 180 kg foam | 4.0 m³ | 45 kg/m³ | Volumetric weight (1,000 kg) |
Freight below roughly a third of the ratio is where quotes go badly wrong, because the gap between the two weights becomes larger than the whole margin on the shipment.
How do you avoid volumetric weight surprises on a quote?
Capture dimensions and stackability at the request stage, never after. Quote on the chargeable weight the engine computes, keep the ratio on the carrier grid, and show the customer the sell price only — the buy rate and the margin stay private.
Most disputes trace back to a missing field, not to a wrong formula. The eight inputs that prevent them: pickup postcode, delivery postcode, gross weight, dimensions per item, item count, stackability, ready date and required options.
Cargavo is a TMS for freight brokers and captures them in a structured request, in the broker's own white-label customer portal, in English, French, Spanish or German. When a rate grid covers the lane, the portal returns a price immediately; when none does, the request becomes a quote request the broker prices by hand — the enquiry is never lost.
Limits. Cargavo does not measure or verify dimensions, does not connect to carrier APIs or EDI, and is not a freight exchange. It prices from the grids you rebuild, with EUR, USD, GBP, CHF, CAD, MAD and PLN available from the Growth plan. Plans are 49, 149 and 399 EUR per month with a 14-day trial.
Frequently asked questions
What is the formula for volumetric weight?
Volume in cubic metres multiplied by the ratio in the carrier tariff. At 250 kg/m³, a shipment of 2.4 m³ has a volumetric weight of 600 kg.
Is 1 m³ always 333 kg?
No. The ratio is set by the carrier in its tariff and varies by carrier and by service. Always read the ratio from the tariff rather than assuming a market default.
Do I include the pallet in the dimensions?
Yes. Volumetric weight uses the loaded dimensions: pallet, packaging, wrapping and any overhang are part of the space the carrier sells.
Does volumetric weight replace the gross weight?
No. It is one candidate among the gross weight, the volumetric weight and the loading-metre equivalence. The highest of them becomes the chargeable weight.