Bulk Cargo Stowage Factor Calculator
Estimate loadable cargo tonnage from hold volume, stowage factor and broken stowage, then check whether the intended quantity fits.
Quick Answer
Need help interpreting this result?
Ask Trade Expert AI how it applies to your transaction. Free with an account.
Overview & methodology
Volume vs Weight Limits
Bulk carriers are subject to two primary constraints: volume (the physical space in the holds) and weight (the deadweight capacity of the vessel). Cargoes like Iron Ore are 'dense' and will cause a ship to reach its weight limit while the holds are still mostly empty. Conversely, light cargoes like Wood Pellets or Grain will 'cube out', filling the holds before the weight limit is reached.
Stowage Factor Formulas
SF (m3/MT) = 1 / Bulk Density (MT/m3)1 m3/MT = 35.8814 ft3/long tonLower SF means a denser cargo that reaches the ship's weight limit before the holds are full; higher SF means a lighter cargo that fills the holds (cubes out) before reaching the weight limit.
Standard Bulk Commodity Stowage Factors (Indicative)
| Commodity | Bulk Density (MT/m3) | Stowage Factor (m3/MT) | Stowage Factor (ft3/LT) | IMO IMSBC Cargo Group |
|---|---|---|---|---|
| Iron Ore Fines | 2.22 - 2.94 | 0.34 - 0.45 | 12.2 - 16.1 | Group A |
| Coking Coal | 0.75 - 0.88 | 1.13 - 1.33 | 40.5 - 47.7 | Group B |
| Steam (Thermal) Coal | 0.72 - 0.84 | 1.19 - 1.39 | 42.7 - 49.9 | Group B |
| Wheat | 0.74 - 0.80 | 1.25 - 1.35 | 44.9 - 48.4 | Group C |
| Corn / Maize | 0.69 - 0.77 | 1.30 - 1.45 | 46.6 - 52.0 | Group C |
| Soybeans | 0.69 - 0.77 | 1.30 - 1.45 | 46.6 - 52.0 | Group C |
| Bagged Rice | 0.65 - 0.74 | 1.35 - 1.55 | 48.4 - 55.6 | Group C |
| Clinker | 1.25 - 1.54 | 0.65 - 0.80 | 23.3 - 28.7 | Group C |
| Bauxite | 1.18 - 1.67 | 0.60 - 0.85 | 21.5 - 30.5 | Group A |
| Fertilisers / Urea | 0.71 - 0.83 | 1.20 - 1.40 | 43.1 - 50.2 | Group C |
Figures above are indicative ranges; always confirm the stowage factor and IMSBC group classification with the cargo shipper's declaration before loading.
Numerical Example: Grain Loading Example
Calculation: (20,000 × 0.98) / 1.35. The 2% broken stowage accounts for space lost at the top and corners of the hold.
Broken Stowage Explained
Broken stowage refers to the space in the hold that cannot be filled by cargo due to the ship's structural frames, pipes, and the angle of repose of the cargo. It is usually expressed as a percentage of the total hold volume and must be subtracted before applying the stowage factor.
Related tools: Draft Survey, Port Drafts.
Method note: calculations run in your browser using the formulas and published rule books cited on this page. Results are free estimates for planning, with no login required, and should be confirmed with your bank, broker or the official source before you commit.
Frequently asked questions
What is stowage factor?
Stowage factor (SF) is the volume (cubic meters) occupied by one metric ton of cargo in a ship's hold. For example, coal has SF ~1.4 m3/MT (dense, compact); grain has SF ~1.25 m3/MT. Lower SF = denser. SF determines how much tonnage fits in a given hold volume.
What is 'broken stowage'?
Broken stowage is wasted space-gaps, voids, and unusable volume in a hold due to its shape and the cargo's shape. A 50,000 CBM hold with 10% broken stowage yields only 45,000 CBM of usable space. Loose dry bulk loaded into grain-capacity holds has close to 0% broken stowage; bagged and breakbulk cargo typically runs 2% to 15%.
How do I know if my cargo fits?
Calculate: Loadable tonnage = (Hold volume × (1 − broken stowage %)) / Stowage factor. Example: 50,000 CBM hold, 10% broken, SF 1.4 = (50,000 × 0.9) / 1.4 = 32,143 MT. If you contract 35,000 MT, it won't fit without partial load.
Related guides & templates
Related calculators
All Bulk Cargo tools →Reviewed by SSLT Global Trade Compliance Team ·Methodology&Primary Sources