About this calculator
Stowage factor (SF) is the space one tonne of cargo takes up in a ship's hold, expressed in cubic metres per metric tonne or cubic feet per long ton. Dense cargo such as iron ore has a low SF, while light cargo such as bagged rice or general packaged cargo has a high SF. For charterers, brokers and planners of bulk carriers and general cargo ships, including inter-island shipments of coal, cement, rice and fertiliser in Indonesia, SF decides how many tonnes can actually be lifted on one voyage.
Holds are rarely filled perfectly. Gaps between bags or cases, the ship's frames, dunnage and the shape of the hold all waste space; that loss is called broken stowage (BS). The calculator works out the space required as tonnes × SF ÷ (1 − BS). When you add the hold capacity (bale for packaged cargo, grain for bulk) and the deadweight available for cargo, it compares the maximum cargo by volume with the maximum by weight. Cargo that fills the space first is measurement cargo (the ship "cubes out"), while cargo that hits the weight limit first is deadweight cargo.
SF can also be derived from the volume and weight of one package, and the result is converted to ft³/LT automatically (1 m³/t ≈ 35.88 ft³/LT). A table of typical SF ranges for some commodities is included for orientation, but the real SF depends on packaging, moisture content and loading method; always use the shipper's figure or official cargo data.
Worked example
A cargo of 1,000 t with SF 1.5 m³/t and 10% broken stowage, then checked against a ship with 20,000 m³ of hold and 15,000 t of deadweight for cargo.
- Space required: 1,000 × 1.5 ÷ (1 − 0.10) ≈ 1,666.7 m³
- Conversion: 1.5 m³/t × 35.88 ≈ 53.82 ft³/LT
- Maximum cargo by volume: 20,000 × 0.9 ÷ 1.5 = 12,000 t, less than the 15,000 t DWT
- For comparison, ore at SF 0.45 could reach 40,000 t by volume, so it is weight-limited
At SF 1.5 this ship cubes out at 12,000 t, before reaching its deadweight limit.
How to use it
Enter the stowage factor
Type the SF in m³/t, pick it from the typical commodity table, or derive it from the volume and weight of one package.
Set the broken stowage
Enter the share of space lost to gaps, frames and dunnage, based on the cargo type and your experience.
Add cargo and ship data
Enter the cargo tonnage to get the space required, and the hold capacity and deadweight for cargo if you want to know the limit.
Read the result
See SF in m³/t and ft³/LT, space required, maximum cargo and whether volume or weight limits it; copy the link to share.