Methodology
How the calculators work, and their limits
The formulas and assumptions behind every tool on this site, and the things a calculator cannot see.
General principles
- Planning estimates, not certified layouts. Results help you plan and compare options. They are not engineering, fire-safety or legal advice, and they do not replace a racking supplier, a truck manufacturer’s data or a qualified layout planner.
- Whole units only. Only whole pallets, bays and rows are counted, and results are rounded down.
- Detail grows with your input. Where a tool can work from less information, the result is labelled with the level of detail it is based on.
- The working is shown. Each calculator lists the steps and figures it used.
- Your figures stay with you. All calculations run in your browser.
What real capacity also depends on
- Building structure, columns and floor load rating
- Fire exits, emergency access routes, walkways and sprinkler clearance
- Door and dock positions
- Forklift turning and manoeuvring space
- Rack type, beam and upright load ratings
- Product characteristics: weight, crushability, stacking limits, temperature needs
- Operational rules: stock rotation, segregation, quarantine and safety procedures
- Local regulations, which always take priority
Tool by tool
| Tool | Method | Main assumptions |
|---|---|---|
| Storage & Capacity Planner | Area only: a repeating module of storage rows and aisles applied to the area after reserved space and a cross-aisle allowance. Length and width: whole rows packed across the floor (single rows at the walls, back-to-back rows between aisles) and whole bays or pallet slots along each row, after wall clearance, reserved space and cross aisles. Levels: ground level plus beam levels that fit below the clear height minus top clearance, limited by equipment lift height. New warehouse: positions needed per level, then the smallest building with the chosen length-to-width ratio that holds them. Count my existing racking: aisles × racked sides × bays per side × pallets per bay × levels, with a height check against the clear height and truck lift height. | Typical aisle and lift figures per equipment type (replaceable); level height = load + 150 mm clearance + 120 mm beam by default; reserved space kept as a strip across one end; default 10% reserved and 10% cross-aisle allowance. |
| Container Load Planner | Whole pallets or cartons on the container floor, trying both orientations and filling leftover length and width with turned units; then layers, weight and volume checks. | Typical internal dimensions and payloads, which vary by container; overhang added on each side; mixed layouts need loading clearance. |
| Trailer Loading | Same floor-layout method as the container planner, for trailer sizes. | Typical trailer dimensions and payloads; axle loads are not checked. |
| Stock Count Variance | Difference = counted − system; accuracy = items within tolerance ÷ items counted × 100. | Tolerance is your own stock policy. |
Testing and corrections
Before a tool is published or changed, its results are checked against hand calculations and against unusual inputs such as zero, negative or very large values. If you find a result that looks wrong, please report it with the figures you entered. Confirmed errors are corrected and the page is updated.
Last updated: September 2026.