How Tariffs Stack in 2026: What Importers Get Wrong

Ask three customs brokers how much duty a shipment owes and you can get three different numbers, and the gap usually isn't a rounding error. It's tariff stacking. Most importers assume every applicable tariff simply adds on top of the last one: base duty, plus Section 301, plus whatever surcharge is active that month. Sometimes that's true. Sometimes it isn't, and the difference can be 10 to 25 percentage points on a single entry.

With Section 122 set to expire on July 24 and a new Section 301 forced-labor tariff already drafted behind it, 2026 has more overlapping duty layers than any year in recent memory. Getting the stacking rules wrong isn't just a paperwork problem. It shows up directly in your landed cost, and it shows up on the wrong side of the ledger either way: overpay because your broker defaulted to adding everything up, or underpay because nobody caught that a newer tariff replaced an older one, and now you owe the difference plus penalties.

The Duty Layers Sitting on a Single Shipment Right Now

A container landing at a US port in July 2026 can be subject to up to four separate duty layers, stacked in this order:

• Base MFN duty: The standard Most Favored Nation rate tied to your product's HTS classification. This applies to nearly everything and rarely changes.

• Section 301 duties: China-specific tariffs, still in place on most of the original List 1 through List 4 product categories, layered on top of the base rate.

• Section 122 surcharge: The 10% universal duty added under Proclamation 11012 since February 24, applying broadly unless a specific exemption applies.1

• Section 232 duties: Product-specific national security tariffs on steel, aluminum, copper, and autos, currently running 25% on steel and 10-50% on aluminum and copper depending on the proclamation in effect.2

Add a countervailing or antidumping duty order on top of that, and a single HTS line can carry five different rates before you've even calculated freight and insurance.

The Rule Most Brokers Get Wrong: Section 232 Doesn't Stack With Section 122

Here's the part that trips people up. The February 24 proclamation that created the Section 122 surcharge carved out an exception: goods already subject to Section 232 duties, meaning steel, aluminum, copper, autos and their listed derivatives, generally do not also get the Section 122 surcharge layered on top.1 You pay the Section 232 rate. You do not pay Section 232 plus 10%.

That sounds simple until you look at what actually counts as "subject to Section 232." The exemption applies to the product covered by the proclamation, not just any product that happens to contain the covered metal. A steel beam is squarely inside Section 232. A finished appliance with a steel bracket inside it usually is not, because the appliance itself isn't the covered article. That appliance pays Section 122 in full, even though its bill of materials includes steel.

There's a second layer of nuance for products that do qualify: the June 2026 update to the metals proclamation requires separating the value of the covered metal content from the non-metal content on the same commercial invoice line. The metal content pays the Section 232 rate. The non-metal content, the plastic housing, the electronics, the packaging built into that same product, still owes Section 122 if the product isn't otherwise exempt.3 A single line item can legitimately carry two different duty treatments at once.

If your customs broker is applying a flat "add every active tariff together" formula to every entry, you're either leaving money on the table on your Section 232 shipments or, more likely, quietly overpaying on products your broker assumed were exempt but actually weren't.

A Real Example: Same Container, Two Different Duty Bills

Say you import steel patio furniture from China. The frames are steel tubing, covered by Section 232 at 25%. The cushions, glass tabletops, and packaging are not.

Priced correctly, that shipment pays: base MFN duty plus Section 301 on the full commercial value, 25% Section 232 on the steel content only, and Section 122 on the non-metal content only, since the steel portion is exempt from Section 122 but the rest of the product isn't. Priced the lazy way, by applying Section 122's 10% to the entire invoice value on top of everything else, you overpay by roughly 10% of your steel content's value on every entry. On a mid-size container program, that's real money disappearing into duties you never owed.

Flip the product category and the mistake runs the other direction. Electronics, apparel, and most consumer goods have no Section 232 exposure at all. If a broker assumes a blanket exemption because "everything gets a metals exception this year," that shipment is now underpaid, and CBP can come back for the difference plus interest and penalties well after the container has cleared.

Why This Matters More in the Next 60 Days

Two things are converging that make stacking errors more expensive right now than they were in April or May. First, import volumes are near record highs. Containerized imports through major US ports are on pace to break the previous monthly record set in 2022, as importers front-load ahead of the Section 122 expiration and the possible forced-labor Section 301 tariff.4 Higher volume means more entries running through the same broker process, and more room for a stacking assumption to get applied uniformly across products it doesn't fit.

Second, CBP's data-matching has gotten stricter across the board this year, and it isn't limited to tariffs. Since July 8, importers of consumer products have had to electronically file Children's Product Certificates and General Certificates of Conformity directly in ACE at time of entry, not after the fact, with civil penalties up to roughly $120,000 per violation for entries where the certificate data doesn't match the importer of record on file.5 That's a separate compliance system from tariff stacking, but it reflects the same trend: CBP is checking entry-level detail more closely than it was 18 months ago, on both duty calculation and product compliance. A landed cost model built on a rough approximation is more likely to get flagged now than it would have been a year ago.

What to Actually Check Before Your Next Entry

• Ask your broker to show the math by HTS line, not as a lump sum. If your customs invoice shows one blended duty percentage for the whole shipment, you can't verify whether stacking was applied correctly. Ask for base MFN, Section 301, Section 122, and Section 232 broken out separately per line.

• Confirm whether your product is "covered" or just "contains" a covered material. This is the distinction that decides whether Section 122 applies on top of Section 232. A component made of steel is not the same as a finished good that happens to include one.

• Check for split-value invoicing on qualifying products. If part of your product's value is genuinely covered metal content, your invoice and entry documentation should separate that value from the rest, so each portion gets the correct duty treatment instead of one rate applied to everything.

• Model your Q3 landed cost under multiple tariff scenarios, not one. With Section 122 expiring July 24 and a forced-labor Section 301 tariff potentially replacing it within weeks, a duty calculation that's accurate today may not be accurate in six weeks. Rerun the numbers rather than assuming July's rate structure holds through Q4.

• Don't treat tariffs and product compliance as separate checklists. A CPSC-regulated product with the correct duty calculation can still get held at the port over an eFiling mismatch. Both have to be right at the same time for the entry to move.

None of this is a reason to avoid ocean freight or slow down your sourcing. It's a reason to want visibility into how each duty layer applies to your specific products, instead of finding out from a broker's invoice after the container has already landed. That's the gap Cubic's customs brokerage team is built to close: entry-level duty tracking that shows you exactly which tariffs apply, and which ones don't, before you pay for either mistake.

If you're not sure whether your current broker is stacking duties correctly on your product mix, talk to our team. We'll walk through your HTS codes and show you where the math actually lands.