Blog · Board and management reporting · Shipping and logistics
How a forwarder or carrier measures detention and demurrage from the container event data and the billing ledger: free time against actual dwell per container, charges incurred from carriers and terminals, charges billed on to customers, the gap between the two per customer, the customers whose containers routinely exceed free time, and the identity that ties charges incurred to charges recovered plus absorbed.
A forwarder pays detention and demurrage to carriers and terminals every month and recovers some of it from customers. The gap is absorbed, per customer, and it is usually caused by a handful of customers whose containers sit past free time on most shipments. The container events and the billing ledger say who and how much. This guide sets out the measures, the recovery gap, the causing customers, and the identity.
Per container:
Dwell at terminal = gate out − discharged; at customer = empty returned − gate out Chargeable days = dwell − free time, floored at zero, per leg Charge incurred, from the carrier or terminal invoice Charge recovered, from the customer billing ledger
Per customer, per period:
Incurred, recovered, absorbed = incurred − recovered Share of containers exceeding free time; median days over
Customer identifiers only.
Σ charges incurred = Σ recovered + Σ absorbed, per period
And every incurred charge maps to a container with events. A charge on a container with no events is listed; it is usually a container number mismatch, and it is unrecoverable until matched.
| Customer | Containers | Exceeding free time | Median days over | Incurred | Recovered | Absorbed | Reading |
|---|---|---|---|---|---|---|---|
| 2207 | 840 | 61% | 6 | $410,000 | $180,000 | $230,000 | Cause and leak |
| 4471 | 520 | 8% | 2 | $31,000 | $29,000 | $2,000 | Fine |
| 9034 | 310 | 44% | 4 | $120,000 | $0 | $120,000 | Never re-billed |
| 1187 | 190 | 12% | 3 | $22,000 | $22,000 | $0 | Recovered in full |
Customer 2207 has six in ten containers over free time and the forwarder absorbs two hundred and thirty thousand dollars a year of the result. Customer 9034 is never re-billed at all, which is a process gap in the forwarder's own billing, not a customer behaviour.
| Pattern | Finding | Owner |
|---|---|---|
| High share over free time, partial recovery | Customer process, and the rate should carry it | Account manager, with the carrier |
| Charges incurred, none recovered | Re-billing process | Billing team |
Incurred tracked; recovery not. The absorbed figure is unknown and assumed small.
Container numbers mismatched. The charge cannot be attributed and is absorbed by default.
Waivers unrecorded. A commercial decision looks like a leak, or a leak looks like a decision.
Customer conversation without the days. The customer disputes the charge; the events end the dispute.
Mapped once, the container events, the free-time terms, the carrier invoices and the customer billing produce the per-container chargeable days, the per-customer recovery gap and the identity every month. Covirage builds this from the exports as they are. The shipping and logistics page describes the setup, and the transit reliability guide covers the other measure built on the same milestone data.
Container event milestones: discharged, gate out, empty returned, from the carrier's or the terminal's data, or the forwarder's own tracking. Free time is on the contract or the carrier's tariff, per trade lane. Dwell minus free time, where positive, is the chargeable period.
Charges arrive from the carrier weeks after the event, often after the customer's invoice has been issued, and the re-billing is manual. Some are disputed. Some are waived for commercial reasons nobody recorded. The absorbed figure per customer makes each of those visible.
For a customer whose containers exceed free time on most shipments, either a longer free-time negotiation with the carrier priced into the rate, or a process change at the customer's site, or both. The report gives the count, the days and the cost, which is more than the customer has usually seen.