IATA TACT Rules
The Air Cargo Tariff and Rules: the industry publication that carries the volumetric divisor, the rounding rules, the rate ladder and the minimum charge.
The Air Cargo Tariff and Rules, published as TACT, is the industry reference that carries the conventions air cargo is quoted and billed on. Rule 3.9.4 sets the volume weight basis at 6,000 cubic centimeters per kilogram, with its imperial equivalents, and prescribes how dimensions and the resulting chargeable weight are rounded. Rule 3.4.1 sets the minimum charge per consignment.
TACT is not a regulation. It is a trade-association publication reflecting inter-carrier agreement, and the antitrust immunity that once covered collective tariff setting has been withdrawn in both the European Union and the United States, so an individual carrier tariff governs where it differs.
The full article will cover the structure of the publication, the volume weight and rounding rules in detail, the general cargo rate ladder and its weight breaks, specific commodity rates, ULD pivot weights, the minimum charge, and the named exceptions that survive inside the rules. The cross-mode comparison is in CBM and chargeable weight .