What a Stacked Tariff Rate Includes (and What It Leaves Out)
2026-11-12
When someone tells me "the tariff on that is 75%," my first question is which lines? A US tariff rate in 2026 is rarely one number. It's a stack: the base rate from the HTS, plus every Chapter 99 duty that applies to that product from that country on that date. Some layers add together, some exempt each other, and a few cap the total.
That's why DutyCite's US tariff calculator shows every layer as its own line, with its own official source and as-of date, and doesn't collapse the stack into one percentage.
Disclaimer: General information only. This isn't customs brokerage, legal advice or a binding classification. For a classification you can rely on, use a CBP binding ruling or a licensed customs broker.
The layers, in order
1. The base rate (Chapters 1–97)
This is the rate on the 8-digit HTS line, usually the "General" (Column 1) rate. It can be ad valorem (a percentage), specific (for example, cents per kg) or compound. A "Special" rate only applies if you qualify for and claim a program. If you need help finding the line, see HTS code lookup.
2. Section 301 duties (Chapter 99)
These are trade-retaliation duties set by USTR. In late 2026 there are two broad kinds:
- China-specific lists from the 2018 investigation, plus the 2024 increases. Examples: 9903.88.01–.04 at +25%, 9903.88.15 at +7.5%, and 9903.91.xx at +25% to +100% for specific products (USITC HTS).
- The forced-labor action on 60 economies, in effect since July 24, 2026: generally +10% or +12.5%, with some economies capped "net of" the MFN rate (Federal Register).
The details are in Section 301 tariffs in 2026.
3. Section 232 duties (Chapter 99)
These are national-security tariffs on specific product groups: metals, autos and parts, trucks, lumber and furniture, semiconductors, pharmaceuticals and more. For metals, since Apr 6, 2026 the duty applies to the full customs value (Federal Register). See how Section 232 tariffs stack.
4. Trade remedies outside Chapter 99
Antidumping and countervailing duties are set per product and per producer under separate orders. They aren't in the HTS rate column, so any calculator that reads only the HTS (mine included) can't tell you whether one applies. Check CBP's AD/CVD resources. The HTS notes for both Section 232 metals and the forced-labor 301 action say AD/CVD "shall continue" to apply (USITC HTS Chapter 99).
5. Fees: MPF and HMF
These aren't tariffs, but you pay them on the same entry: the MPF (0.3464%, with a minimum and maximum) and, for ocean cargo, the HMF (0.125%). See MPF and HMF fees in 2026.
How the layers interact
This is where most estimates go wrong. Three rules from the current HTS notes do most of the work:
- The forced-labor 301 duty generally stacks on other Chapter 99 duties. U.S. note 52(a) says products subject to these headings "shall also be subject to any additional duty provided for in this subchapter," except as the note provides (USITC HTS Chapter 99).
- But it doesn't apply to Section 232 goods. Note 52(f) and heading 9903.05.90 exclude articles of aluminum, steel or copper and their derivatives under the 232 metal headings, plus 232 autos and parts, trucks, wood products, semiconductors and patented pharmaceuticals (USITC HTS).
- The 232 metal headings are mutually exclusive. U.S. note 16(a) says "an imported article will be subject to no more than one of these headings" (USITC HTS Chapter 99).
Some newer headings also use caps instead of add-ons. For example, the forced-labor action sets some economies' rate "net of a product's most-favored-nation (MFN) duty," so the base rate and the 301 duty together reach a fixed level (Federal Register).
Worked example: steel bolts from China
Assumptions: bolts, HTS 7318.15.20 ("Bolts and bolts and their nuts or washers entered or exported in the same shipment"). Product of China. Customs value $50,000. Ocean freight. Formal entry. As of Nov 12, 2026.
| Layer | Heading / source | Rate | Amount |
|---|---|---|---|
| Base | 7318.15.20, General (1) | Free | $0.00 |
| Section 301, China List 3 | 9903.88.03; 7318.15.20 is listed in U.S. note 20(f) (1, 5) | + 25% | $50,000 × 0.25 = $12,500.00 |
| Section 232, derivative steel | 9903.82.02; 7318.15.20 is listed in U.S. note 16(c)(iv) (1, 5) | + 50% on full value | $50,000 × 0.50 = $25,000.00 |
| Section 301, forced-labor (China 9903.05.31) | Excluded by note 52(f)(1) / 9903.05.90 because it's a 232 metal article (1) | n/a | $0.00 |
| MPF | 19 CFR 24.23; FY2027 limits (6, 7) | 0.3464% | $50,000 × 0.003464 = $173.20 |
| HMF | 19 CFR 24.24 (8) | 0.125% | $50,000 × 0.00125 = $62.50 |
| Total | $37,735.70 |
The duty stack here is 75% (0% + 25% + 50%). Notice what isn't in it: China's 12.5% forced-labor duty, because the 232 exemption removes it. If you added every China rate you'd heard of, you'd overstate this entry by $6,250.
Two cautions specific to this example:
- Exclusions: some specific bolts once had Section 301 exclusions. The HTS compiler's note says only exclusions in note 20(vvv) and (www) are still in effect. USTR extended the remaining 178 exclusions through Jan 9, 2027 (Federal Register). Check whether your exact product is one of them.
- AD/CVD: steel fasteners can be subject to antidumping or countervailing orders. I didn't check that here. Do it before importing.
Rates change. Re-verify every line on your import date.
Why I show the stack, not just the total
A single "75%" can't be audited. A stack with headings and sources can. If a rate changes, you can see which line moved and why. I designed DutyCite's calculator around that idea: each line carries its source and as-of date. The HTS lookup helps with the code, and developers can find the API and MCP details in the docs and on the pricing page.
For a China-focused version with a different product, see the China tariff walkthrough.
Checked Nov 12, 2026 against 2026 HTS Revision 23.
References
- USITC, Harmonized Tariff Schedule (live search; 2026 Revision 23). https://hts.usitc.gov/
- Federal Register, USTR, "Notice of Actions in Section 301 Investigations ... Forced Labor," 91 FR 47318 (Jul 28, 2026). https://www.federalregister.gov/documents/2026/07/28/2026-15181/notice-of-actions-in-section-301-investigations-of-acts-policies-and-practices-of-various-economies
- Federal Register, Proclamation 11021, 91 FR 18201 (Apr 9, 2026). https://www.federalregister.gov/documents/2026/04/09/2026-06960/strengthening-actions-taken-to-adjust-imports-of-aluminum-steel-and-copper-into-the-united-states
- CBP, Antidumping and Countervailing Duties. https://www.cbp.gov/trade/priority-issues/adcvd
- USITC, HTS Chapter 99 (current release PDF, U.S. notes 16, 20 and 52). https://hts.usitc.gov/reststop/file?release=currentRelease&filename=Chapter%2099
- eCFR, 19 CFR 24.23. https://www.ecfr.gov/current/title-19/chapter-I/part-24/section-24.23
- Federal Register, CBP, "Customs User Fees To Be Adjusted for Inflation in Fiscal Year 2027," 91 FR 48398 (Jul 31, 2026). https://www.federalregister.gov/documents/2026/07/31/2026-15530/customs-user-fees-to-be-adjusted-for-inflation-in-fiscal-year-2027
- eCFR, 19 CFR 24.24. https://www.ecfr.gov/current/title-19/chapter-I/part-24/section-24.24
- Federal Register, USTR, "Notice of Product Exclusion Extensions," 91 FR 72610 (Nov 10, 2026). https://www.federalregister.gov/documents/2026/11/10/2026-22925/notice-of-product-exclusion-extensions-chinas-acts-policies-and-practices-related-to-technology