General Average Calculator

General average is the maritime-law principle that when cargo, fuel, or equipment is deliberately sacrificed — jettisoned to save a foundering ship, for example, or damaged fighting a fire — everyone with a financial stake in the voyage shares that loss proportionally, not just the owner of the sacrificed goods. This calculator implements that proportional split under the York-Antwerp Rules — a voluntary set of general-average rules maintained by the Comité Maritime International, most recently updated in 2016, that shipowners and cargo interests incorporate into bills of lading and charter parties by contract: it adds vessel value, total cargo value, and freight at risk together to get the total voyage value, then calculates each party's percentage share of that total. Your GA contribution is simply your cargo's share of the voyage value multiplied by the total GA loss being distributed, and the same math produces the vessel owner's contribution from the vessel's share.

The calculator also estimates a GA deposit — a cash security typically running around 10% of cargo value that average adjusters require upfront from cargo owners before releasing goods, well before the final contribution amount is settled. A key point this tool can't fully substitute for: general average adjustment is a formal legal process run by a professional average adjuster, often taking months or years to finalize, and the percentages here are a simplified proportional estimate rather than the adjuster's final apportionment, which can account for additional factors like partial losses and expenses already incurred. Because contributions can be substantial, cargo owners should confirm their marine cargo insurance policy (an Institute Cargo Clauses A policy or equivalent) explicitly covers general average obligations before a voyage, not after a casualty has already occurred.