If you're importing something covered by more than one tariff action right now, the question that actually matters isn't "what's my rate" — it's "do these add together, or does one replace the other?" The answer is neither simple nor consistent across authorities, and getting it wrong in either direction costs you: overpaying if you stack tariffs that don't actually combine, or under-budgeting if you assume something doesn't stack when it does.
One thing worth clearing up first: if you've read about Section 122 stacking rules elsewhere, that program expired on July 24, 2026 and was replaced the same hour by a new Section 301 action — covered in full in our post on that transition. Everything below reflects what's actually current.
Start with the base rate — this always applies
Every import has an MFN (Most Favored Nation) base duty rate, published in the Harmonized Tariff Schedule. This is your floor. Everything below adds to it — nothing removes it.
Section 232 and the new Section 301 forced-labor action generally don't stack
Goods already covered by an active Section 232 action (steel, aluminum, copper, autos, semiconductors, lumber) are exempted from the new Section 301 forced-labor tariffs that replaced Section 122. You pay the applicable 232 rate on those goods, not both — the same non-stacking principle that governed Section 122 carried over to its replacement.
The exception that catches people off guard: for composite or derivative products with both metal and non-metal content, Section 232 applies to the metal-content portion of the value, while the non-metal portion can still carry the separate tariff. A steel appliance with a plastic housing isn't automatically "all 232" just because the core material is steel. If your product isn't pure raw material, this split is worth checking specifically.
There are two different Section 301 tracks — don't confuse them
This is the mistake most likely to cost you: "Section 301" isn't one program.
Track 1 — the original China-specific lists (active since 2018). These predate everything else discussed here, range from 7.5% to 100% depending on the product list, and are unaffected by the 2026 changes below. If you import from China, check whether your HTS code sits on one of these original lists first.
Track 2 — the new forced-labor action (effective July 24, 2026). This replaced Section 122 and covers roughly 60-80 economies, not just China. The rate depends on your specific country:
- Flat 10% for economies with an existing forced-labor import ban, commitment, or partial regime — including Canada, Mexico, India, Indonesia, and the UK.
- Net-of-MFN, capped at 10% for the EU and Taiwan — meaning the tariff tops up whatever they already pay to 10% combined, with zero additional duty if their MFN rate already clears that bar.
- Net-of-MFN, capped at 12.5% for Japan, South Korea, and Switzerland, using the same capping logic.
- Flat 12.5% for every other economy covered by the investigation, including China (on top of whatever China already owes under Track 1 above).
AD/CVD stacks on top of everything
Antidumping and countervailing duties (AD/CVD), where they apply to your specific product and country, stack on top of all of the above. These are calculated separately per case and aren't affected by the Section 232 exclusivity rule.
USMCA still matters
USMCA-qualifying goods from Canada and Mexico are exempt from the forced-labor Section 301 action. They are not exempt from Section 232 — steel, aluminum, and copper tariffs still apply regardless of USMCA status.
Putting it together: a worked example
Say you import a steel component from China with a small polymer housing:
- MFN base rate — applies to the full value.
- Section 232 steel — applies to the steel-content portion of the value.
- Original China Section 301 list tariff — applies on top, since it's a separate, unaffected track.
- New forced-labor Section 301 (12.5%, China tier) — applies to the non-steel portion not covered by Section 232.
- MPF and HMF — apply on top of the final customs value, per our tariff calculator.
Multiple layers, on one shipment, none of which show up if you only check one authority in isolation.
What to actually check before you assume a rate
- Is your product covered by an active Section 232 category? If yes, that's your starting layer for that portion of the value.
- Is your product a composite of metal and non-metal materials? Don't assume 232 covers the whole value — check the split.
- If you're sourcing from China, check both the original 2018-era Section 301 lists and the new forced-labor tier — they're separate and can both apply.
- Do you qualify for USMCA? That removes forced-labor Section 301 exposure specifically — not Section 232.
This reflects the tariff stacking hierarchy as of August 2026, following Section 122's July 24 expiration and replacement — not legal or customs advice. Stacking rules, especially around composite-product valuation splits and the two separate Section 301 tracks, are genuinely complex and worth confirming with a licensed customs broker for your specific product and HTS classification before relying on any figure above.