ENGINEERING ARCHITECTURE

Calculation Methodology & Architecture

How calculations, packing heuristics, and unit systems are architected across the platform.

1. Unit Normalization Engine

Calculations normalize all user inputs into canonical SI units internally before performing mathematical operations:

  • Length: Normalized to meters (m) using exact factors (1 in = 0.0254 m; 1 mm = 0.001 m).
  • Mass / Weight: Normalized to kilograms (kg) using exact factors (1 lb = 0.45359237 kg).
  • Volume: Normalized to cubic meters (m³) and liters.

After calculations complete, values are converted back to the user's selected unit and formatted with locale-safe, context-appropriate decimal precision.

2. Rectangular Packing Heuristics

Unlike generic calculator websites that divide container volume by carton volume, our engines run deterministic 2D and 3D rectangular packing heuristics:

Pallet Layer Geometry (TI × HI)

Evaluates aligned and rotated rectangular floor patterns, mixed strip arrangements, and vertical layer constraints. Checks payload ratings, deck height allowances, and carton overhang limits.

Trailer Floor & Pallet Packing

Packs items across usable trailer widths (e.g. 2.4 m European trailers or 96" North American dry vans) to find the shortest continuous floor length (linear feet / loading meters).

3D Container Packing

Evaluates multiple layer orientations and floor placements. Calculates actual Cartesian coordinate bounding boxes [x, y, z, l, w, h] to guarantee zero overlaps and verify equipment bounds.

3. Freight Density & Classification Boundary Logic

Freight class lookup utilizes the current NMFTA 13-sub full-scale density schedule. Boundary handling uses normalized half-open intervals: min ≤ density < max. For example, a density of exactly 15.000000 lb/ft³ is classified as Class 70 (15 to <22.5 PCF), avoiding floating-point precision threshold bugs.

4. Source Hierarchy & Verification Protocol

All reference specifications follow a strict source priority:

  1. Primary Standards Bodies: ISO (ISO 6780 for pallets) and EPAL.
  2. Industry Associations: NMFTA (FCDC density schedules) and IATA (volumetric cargo conventions).
  3. Equipment Specifications: Official container line specifications (Maersk, MSC, Hapag-Lloyd).
  4. Carrier Service Guidelines: Published tariff rules from national parcel carriers (UPS, FedEx).