Demurrage vs detention vs storage: separate the container charge clocks

What is the difference between demurrage, detention and storage?

The FMC describes demurrage as accruing when a container exceeds free time on a marine terminal and detention as a charge for extended use of intermodal equipment. Outside that U.S. context, check local terms and the actual invoice description. Even within one shipment, a carrier’s combined free-time arrangement may differ from a terminal or depot’s separate storage rule.

Use the comparison below to organize the review, not to assign legal liability. A label on an invoice is not enough to determine the applicable service or rule. Identify where the cargo or equipment was, which party supplied the service, the agreed allowance and the event that ended the relevant period.

Why does “five free days” not settle the calculation?

An allowance is incomplete without its clock. Record the triggering event, start date, time zone, whether days are calendar or working days, how weekends and holidays are treated, and whether the period combines demurrage and detention. Confirm whether the start/end days count and whether the rule changes by equipment, route or agreement.

Keep the applicable tariff or contract version and the source-confirmed last free day where supplied. Do not infer a universal allowance from a previous shipment, an online example or a carrier’s rule for another country. If the available record says only “free time,” ask which service and container it covers before forecasting cost.

A vessel arrival, container discharge, cargo availability, customs release, gate-out and empty return are different events. A customs release alone does not prove that collection was possible; conversely, an internal delay does not by itself establish that a charge is invalid. Preserve the actual circumstances for review.

Worked example: two free-time clocks, not one ETA date

These fictional terms use calendar days, include the triggering day in free time and charge the pickup/return day. Assume availability on 12 October, five terminal free days (12–16 October), and pickup on 19 October. Separately assume four equipment free days from gate-out (19–22 October), and accepted empty return on 26 October. Actual contracts may count differently.

Terminal charge days are 17–19 October: 3 × USD 100 = USD 300. Equipment charge days are 23–26 October: 4 × USD 75 = USD 300. The illustrative total is USD 600 before any separate storage, tax or adjustment. The chosen rates are assumptions, not a tariff quotation. Warehouse delivery is not substituted for accepted empty return.

Retain the actual free-time confirmation, availability and gate records, return-location instructions, appointment attempts, accepted empty-return receipt and invoice. Assess service-specific terms and dispute deadlines separately; this arithmetic does not decide whether a charge is enforceable.

• Use the ETA exception checklist
• Compare a documented cost variance

How do you check a tiered demurrage calculation?

Illustrative arithmetic only: assume one container, an agreed last free day of 10 September, and exactly three chargeable calendar days: 11, 12 and 13 September. Assume the applicable example tariff charges 100 currency units per day for chargeable days 1–2 and 150 for day 3. These are invented teaching inputs, not a quoted carrier rate.

The example charge is (2 × 100) + (1 × 150) = 350 currency units. It excludes taxes, exchange conversion, storage and detention. The actual invoice may use different tiers, day-count conventions or combined rules. Reproduce those actual terms before comparing the billed amount.

• Verify the container and service period before applying a rate.
• Count chargeable days using the actual start/end and holiday rules.
• Assign each day to its correct tier; do not apply the highest rate to every day.
• Keep separate equipment, storage, tax and adjustment lines identifiable.
• Retain credits and disputed amounts separately from accepted cost.

Which records help reconstruct the charge period?

Build one evidence timeline with source, event time and time received. The operations team should be able to explain what prevented collection or return, when that condition changed and what action was attempted. An invoice period and an internal spreadsheet date are claims to reconcile, not independent proof of availability.

For an empty return, preserve the nominated return location, any changes to it, appointment attempts and the eventual acceptance receipt. A delivered container can still be outside the agreed return point. For terminal collection, retain availability messages and the specific release or appointment information relevant to the period.

What U.S. billing-rule details should the reviewer verify?

For U.S. ocean shipments, review the current FMC framework and the billing party’s role. The FMC’s published explanation distinguishes the invoice clock for vessel-operating carriers and marine terminal operators from the NVOCC clock: the former is measured from when charges were last incurred; the latter from issuance of the invoice received. Its stated issuance period is 30 calendar days.

The same explanation describes at least 30 calendar days for fee mitigation, refund or waiver requests, with a timely request triggering an attempted resolution within 30 days unless the parties agree longer. Record the actual receipt and request evidence; do not turn this outline into a universal payment due date or a guarantee of a waiver.

Read the later court update with the original 2024 announcement. The FMC reported that the court set aside section 541.4, concerning who could be invoiced, while the remaining billing rule stayed in effect. Do not copy the original article’s now-vacated bill-to restriction into a 2026 operating checklist. Have the responsible reviewer assess the current rule and actual invoice before deciding liability.

A six-step review before a charge becomes accepted landed cost

Assign one person to coordinate the review and preserve the relevant contractual or regulatory deadlines. Request missing information precisely: identify the container, period, field or rate in question and the source that conflicts with it. A broad statement that “the shipment was delayed” does not explain the disputed charge interval.

Operational review and payment authority are separate. Finance needs to know which amount is accepted, which is queried, who owns the decision and whether a credit or other resolution is pending. Do not silently delete a disputed invoice or count both the original amount and its replacement as separate accepted costs.

• Identify the invoice, issuer, billed party, shipment and container.
• Separate demurrage, detention, storage and other service lines.
• Reconstruct the relevant event and free-time clocks from retained sources.
• Recalculate days, tiers, quantities and adjustments under the actual terms.
• Send a documented query through the proper channel within applicable deadlines.
• Record acceptance, credit, payment or escalation with evidence and a responsible owner.

Measure preventable process gaps without inventing savings

Track invoice evidence completeness as reviewed invoices with all required operating records divided by invoices reviewed. Track response timeliness using the number of queries submitted before the applicable deadline divided by queries due. Publish the cohort and missing records; these are process measures, not findings of compliance.

Classify the reason for each rework cycle: wrong reference, unknown free-time rule, unavailable release evidence, return-location change, rate mismatch or missing credit. Improve the handoff that repeatedly creates the gap. Report verified credits separately from hypothetical avoided charges; a reduction in invoices alone does not establish that the process caused a saving.

Keep the accepted cost connected to the supporting shipment

Use Tyllus to connect shipment cost records, documents, partner context and follow-up work. When a charge is reviewed, retain the invoice evidence and the recorded decision so finance can trace the accepted figure to its source rather than an unexplained total.

Tyllus does not decide whether a carrier charge is legally enforceable, promise a successful dispute or replace qualified advice. The useful operating outcome is a clear record: the service, period, evidence, accepted amount, open question and person responsible.

Common container-charge questions

Are demurrage and detention the same? They commonly concern different terminal and equipment-use periods. Check whether the actual agreement combines them.

Does warehouse delivery end detention? Not necessarily. Verify the agreed equipment-return condition and the record showing it was satisfied.

Can storage and demurrage both appear? Separate services or billing arrangements can produce distinct lines. Inspect the actual terms and periods rather than assuming either automatic duplication or automatic validity.

Does a port closure automatically cancel every charge? No universal conclusion follows. Preserve the circumstances and applicable rule for the responsible reviewer.

Is a last free day always calculated from ETA? No. Obtain the relevant allowance and triggering event from the applicable source.