Every formal US customs entry carries a Merchandise Processing Fee (MPF) of 0.3464 percent of the shipment value and, for ocean shipments, a Harbor Maintenance Fee (HMF) of 0.125 percent. Together they add about half a percent to your landed cost on every container. They are set by statute, not negotiable, and missing them means your product margins are thinner than your spreadsheet says.
What the Merchandise Processing Fee actually is
The MPF funds the commercial operations of US Customs and Border Protection, and it applies to formal entries of merchandise imported into the US. For 2026 the rate is 0.3464 percent of the entered value, with a minimum of about $31 and a maximum of about $614 per entry. Small shipments pay the floor; very large ones are capped, which is why consolidating entries can shave the fee on a per-unit basis.
Where importers go wrong is treating the MPF as a rounding error. On a $60,000 container it is roughly $208, small next to duty but real. And it is assessed per entry, not per shipment: if your broker files three separate entries for one vessel arrival, you pay the MPF three times. Ask your broker how many entries they file per arrival, because the answer is directly money.
The Harbor Maintenance Fee and when it applies
The HMF is 0.125 percent of cargo value and applies to ocean shipments unloaded at US ports, paid by the importer on a quarterly basis through CBP. It does not apply to air freight, land border crossings from Canada or Mexico, or shipments that merely transit US ports. If you import by sea from Asia or Europe, it applies to you.
The HMF is self-reported: you (or your broker) calculate it and pay it quarterly, with payment due within 31 days of the quarter's end. Many small importers do not realize they owe it at all, since no bill arrives in the mail. CBP can audit years of HMF payments, and interest on underpaid quarters compounds. If you have been importing by ocean for years and never heard of the HMF, check with your broker now.
Where both fees appear on your entry
On a CBP Form 7501, the MPF appears in block 39 as a separate line from duty, and the HMF shows up in its own block on ocean entries. Pull one entry summary from your broker and find both numbers. If your broker files through ABI, ask for the electronic entry summary extract: the fee lines are there too, just formatted differently.
This matters because landed-cost models usually sum product cost, freight, insurance, and duty, then add a fudge factor. Make the fees explicit instead: product + freight + insurance + duty + MPF + HMF. On a typical 15 percent duty rate shipment, the two fees add roughly three percent to your total import tax line. That is the difference between a 55 percent and a 53 percent gross margin on some SKUs.
Modeling MPF and HMF in your per-unit landed cost
The straightforward way: for each planned shipment, compute MPF as 0.3464 percent of the entered value (bounded by the annual floor and ceiling, which CBP adjusts for inflation), and HMF as 0.125 percent for ocean cargo. Divide each by the unit count and add the per-unit figures to your landed cost alongside duty. Because the MPF is per entry, your per-unit fee drops as entry values rise toward the cap, another reason to consolidate.
A practical shortcut many Shopify importers use is a blended import-fee rate of 0.5 percent on ocean shipments and 0.35 percent on air and land, applied to the entered value before duty. It is not exact, but it beats zero, and you can refine it quarterly when your broker sends the real numbers. The goal is not perfect precision; it is that your margin math reflects money you actually spend.
Common mistakes that cost real money
The most expensive mistake is duplicate MPF from fragmented entries: split shipments arriving on different days, or a broker who files one entry per container instead of one per arrival. The second is ignoring HMF entirely until an audit letter arrives, which turns a routine payment into interest plus penalties. The third is modeling fees on FOB value but paying duty on a different valuation base; keep the base consistent across duty, MPF, and HMF, which is generally the entered (transaction) value.
Fix all three with one quarterly habit: reconcile what you paid against what you modeled. Your broker can give you a quarterly summary of entries, MPF, and HMF by shipment. Compare it to your spreadsheet, adjust the model, and the drift stops. Import fees will never be the biggest line in your landed cost, but they are the easiest one to get exactly right, which makes them the cheapest margin points you will ever find.
Do I pay MPF on informal entries under $2,500?
No. Informal entries are exempt from the MPF, which is one reason many small Shopify importers never see the fee until their shipments grow. Once you move to formal entries, the MPF applies from the first one.
Does the HMF apply to air freight?
No. The Harbor Maintenance Fee applies only to ocean shipments loaded or unloaded at US ports. Air cargo, truck and rail from Canada and Mexico, and in-transit cargo are exempt. If you split freight between ocean and air, only the ocean portion carries the HMF.
Who pays the HMF, me or my freight forwarder?
The importer of record owes the HMF, and it is typically paid through your customs broker quarterly. Freight forwarders may advance it and bill you back, but the liability is yours, so confirm someone is actually filing and paying it.