Calculate and dispute demurrage and detention charges using terminal and ocean carrier API data to build an evidence package
domain: inttra.com · 5 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Retrieve the container's actual terminal gate-in and gate-out timestamps from the ocean carrier or terminal operator API, including the free-time start date as defined by the carrier's tariff
Pull the carrier's published demurrage and detention tariff rates via their API or rate card, noting any agreed contract exceptions or free-time extensions
Calculate the chargeable days by subtracting free time from the actual dwell, applying weekend and holiday exclusions per the specific tariff terms
Compare the carrier's invoice to your calculated liability, flagging discrepancies caused by incorrect free-time start dates, misapplied tariff levels, or duplicate charges
Compile the dispute package with terminal gate receipts, booking confirmation, and delay documentation (port congestion, carrier-caused delays) and submit via the carrier's dispute portal
Known gotchas
Free time start date definitions vary by carrier: some start the day after discharge, others on the day of discharge; read the carrier tariff clause precisely before calculating
Many carrier tariffs exclude weekends and holidays from detention free time but not demurrage free time; conflating the two produces incorrect liability calculations
Dispute windows are typically 30-90 days from invoice date; missing the window forfeits the right to contest even a clearly erroneous charge
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