Stowage Factor Calculator
Calculate cargo stowage factor from cargo volume and weight, or calculate the cargo volume and weight from a known stowage factor. Results are shown in both m³/tonne and ft³/ton.
Stowage Factor Result
What is stowage factor?
Stowage factor is the volume occupied by one unit of cargo weight. In shipping, it is commonly expressed as cubic meters per metric tonne (m³/tonne) or cubic feet per ton.
Stowage factor formula
$$SF = \frac{Cargo\ Volume} {Cargo\ Weight}$$
When volume is measured in m³ and weight in metric tonnes:
$$SF = \frac{m^3}{tonne}$$
How do you calculate cargo volume from stowage factor?
Rearranging the formula gives:
$$Cargo\ Volume = Stowage\ Factor \times Cargo\ Weight$$
For example, if a cargo has a stowage factor of 1.25 m³/tonne and weighs 800 tonnes:
$$Volume = 1.25 \times 800 = 1,000\ m^3$$
How do you calculate stowage factor from volume and weight?
Divide cargo volume by cargo weight:
$$SF = \frac{Volume}{Weight}$$
For example, 1,000 m³ of cargo weighing 800 tonnes has:
$$SF = \frac{1000}{800} = 1.25\ m^3/tonne$$
How do you convert m³/tonne to ft³/ton?
The conversion depends on whether the ton is metric, short, or long. For metric tonnes:
$$1\ m^3 = 35.3147\ ft^3$$
$$SF_{ft^3/t} = SF_{m^3/t} \times 35.3147$$
For example:
$$1.25\ m^3/t \approx 44.14\ ft^3/t$$
How do you convert ft³/ton to m³/tonne?
For metric tonnes:
$$SF_{m^3/t} = \frac{SF_{ft^3/t}} {35.3147}$$
What is cargo density?
Cargo density is the inverse of stowage factor when compatible units are used:
$$Density = \frac{Weight}{Volume}$$
$$Density = \frac{1}{SF}$$
For example, a stowage factor of 1.25 m³/tonne corresponds to a theoretical cargo density of approximately 0.80 tonnes/m³.
What is broken stowage?
Broken stowage is the space that cannot be completely occupied by cargo because of gaps between packages, irregular shapes, structural obstructions, access requirements, or inefficient stowage.
$$Space\ Required = Base\ Cargo\ Volume \times \left( 1 + \frac{Broken\ Stowage}{100} \right)$$
For example, if 1,000 m³ of cargo requires 5% additional space:
$$1,000 \times 1.05 = 1,050\ m^3$$
Stowage factor example
A cargo weighs 500 tonnes and occupies 650 m³. Its stowage factor is:
$$SF = \frac{650}{500} = 1.30\ m^3/tonne$$
If 5% broken stowage is expected:
$$650 \times 1.05 = 682.5\ m^3$$
Stowage Factor Reference Examples
Different cargoes can have very different stowage factors. Packaging, moisture, particle size, voids, and the way cargo is presented can materially change the actual space occupied.
| Example Cargo Type | Stowage Factor Tendency | Space Consideration |
|---|---|---|
| Dense bulk mineral cargo | Low | High weight relative to volume |
| Grain | Moderate | Flows into available spaces relatively well |
| Wood products | High | Large volume for the cargo weight |
| Bagged cargo | Moderate to high | Package geometry creates void spaces |
| Vehicles / machinery | High | Irregular geometry and substantial broken stowage |
Why is stowage factor important in shipping?
Stowage factor helps determine how much cargo space is needed for a given cargo weight. It is therefore important when estimating whether available hold volume or container space can accommodate a cargo.
Does a higher stowage factor mean lighter cargo?
Generally, yes. A higher stowage factor means more volume is required per unit of weight, so the cargo has a lower density.
What is the difference between stowage factor and density?
They describe opposite relationships:
$$Stowage\ Factor = \frac{Volume}{Weight}$$
$$Density = \frac{Weight}{Volume}$$
Thus, with compatible units:
$$Density = \frac{1}{Stowage\ Factor}$$
What does a stowage factor of 1.5 mean?
A stowage factor of 1.5 m³/tonne means one metric tonne of cargo occupies approximately 1.5 cubic meters before any additional allowance for broken stowage.
What does a stowage factor of 2.0 mean?
A stowage factor of 2.0 m³/tonne means each metric tonne requires approximately 2 cubic meters of cargo volume. It therefore represents a less dense cargo than a cargo with a stowage factor of 1.0 m³/tonne.
Stowage factor FAQ
Stowage factor = cargo volume ÷ cargo weight. It is commonly expressed as m³/tonne or ft³/ton.
Multiply stowage factor by cargo weight. Volume = SF × weight.
No. Stowage factor is volume per unit weight, while density is weight per unit volume. With compatible units, they are inverses.
A high stowage factor means the cargo occupies a relatively large volume for its weight and therefore has relatively low density.
Broken stowage is space that cannot be fully occupied because of gaps, cargo shape, packaging, structural features, or required access space.
Common units include cubic meters per metric tonne (m³/tonne) and cubic feet per ton (ft³/ton).