The freight rate you were quoted isn’t what you’ll pay. Between the container rate and the final cost sits a family of charges that almost nobody explains up front, and that can double the logistics cost of a poorly handled shipment: demurrage, detention and storage. All three punish the same thing — a container or cargo sitting longer than allowed — but they’re billed by different people, for different reasons. Here’s the difference and how to keep them from eating your margin.
The three charges, without confusing them
| Charge | Who bills it | What it punishes | Where it happens |
|---|---|---|---|
| Demurrage | Carrier | A full container sitting inside the terminal past the free days | Inside the port/terminal |
| Detention | Carrier | The container (the equipment) held outside the terminal past the free days | At your warehouse/plant |
| Storage | Terminal/precinct | Occupying space in the bonded precinct | Inside the port/terminal |
The key distinction: demurrage and detention are billed by the carrier for their container; storage is billed by the terminal for its space. A single stuck container can rack up demurrage and storage at the same time, because they’re two separate clocks running in parallel.
Demurrage
It starts when the full container is discharged and stays in the terminal beyond the free days the carrier grants. As long as you don’t pull it out, the container occupies the carrier’s equipment inside the port. The charge is per container, per day, and usually escalates: one rate for the first days, a higher one after, then a higher one still.
Detention
It starts when you pull the full container out of the terminal to your warehouse to unload, but take longer to return it empty than the agreed free days. Here the penalty is for keeping the carrier’s equipment outside the port. Same structure: per container, per day, tiered.
Mental rule: demurrage = the container didn’t leave the port on time. Detention = the container left but didn’t come back empty on time.
Storage
Billed by the bonded precinct (the port terminal or yard) for the space occupied while cargo waits for clearance. It runs in parallel with demurrage and usually has its own free days, different from the carrier’s. Confusing the two clocks is an expensive mistake: you may think you have room because the carrier gave you 7 free days, while the precinct only gave you 3.
How many free days you get (and why it matters)
There’s no single standard: it depends on the carrier, the route, the contract and the terminal. Typical ranges in Mexico:
- Demurrage: 4 to 7 free days common; some carriers grant more under volume contracts.
- Detention: 3 to 5 free days common once the container is pulled.
- Storage: 2 to 5 free days from the precinct, often fewer than the carrier’s.
The number is negotiable. A forwarder with volume can get you more free days than you’d obtain on your own — and those extra days are worth more than a freight discount when clearance gets complicated.
The five real causes of extra charges
1. Incomplete or late documentation
The #1 cause. If the invoice, packing list, BL, certificate of origin or permits aren’t complete and correct before arrival, clearance doesn’t move and the clock runs. (See customs clearance step by step.)
2. Bad tariff classification
A wrong code triggers a review, a query or even a PAMA proceeding. The container sits racking up demurrage and storage while it gets sorted out. (See tariff classification.)
3. Red light / physical customs inspection
If you draw an inspection, the goods wait their turn for physical review. You don’t control that, but you can have everything so in order that the review resolves fast instead of escalating into a query.
4. A missing NOM or permit discovered on arrival
Arriving without the labeling NOM or the prior permit the tariff code required means the goods can’t be released until you regularize — and sometimes you have to label inside the precinct, adding time and storage.
5. Lack of inland transport coordination
Clearance is released, but there’s no truck available to pull the container the same day. Every day of waiting is demurrage. Pickup and transport must be scheduled before release, not after.
How to avoid them (one line each)
- Document pre-validation 5–10 days before arrival.
- Tariff classification validated before quoting, not on arrival.
- NOMs and permits confirmed from the purchase order.
- Transport scheduled against the estimated release date.
- Free days negotiated by volume through the forwarder.
The costliest miscalculation
Choosing freight on price without looking at free days or the provider’s clearance capability. A carrier that’s $200 cheaper with 3 free days can cost you far more than one that’s $200 more expensive with 7, if your clearance stalls for two days. Freight is one line of the cost; demurrage charges are the line that doesn’t appear in the initial quote and that ends up deciding whether the operation was profitable.
At TradeWay
We handle the shipment and the clearance as a single operation, precisely so the demurrage, detention and storage clocks don’t start running against you. We pre-validate documentation before arrival, classify and confirm NOMs and permits from the start, and schedule inland transport against the estimated release date to pull the container the same day. With forwarding, customs clearance, warehousing and transport under a single point of contact and a single invoice, there are no coordination gaps between vendors — which is exactly where extra charges are born. If you want to know how much delays are really costing you, send us your last operation and we’ll break it down with you.
