Most duty-saving conversations start in the wrong place — with the country of origin, or with a trade agreement. For a large share of US import programs the money is closer to home: the tariff line itself. In 61.4% of US subheadings that contain more than one rate-bearing line, those sibling lines disagree on the duty rate — and the facts that separate them are often not written anywhere on a supplier's invoice.
Check your own codes against this analysis. The figures below come from all 13,801 published lines. The free Duty Spread Checker runs the same comparison on any code you enter and tells you what the gap is worth against your annual volume.
Duty is not set at the 6-digit subheading that most people quote. It is set at the 8- or 10-digit line underneath it. A single subheading can hold several lines that split on a physical or commercial fact: value per pair, material of the upper, whether an article is of a kind used for a particular purpose, size, or composition by weight.
We analysed every published line in the current schedule. Of the 611 six-digit subheadings that contain two or more percentage-rate lines:
| Finding | Subheadings | Share |
|---|---|---|
| Sibling lines carry different rates | 375 | 61.4% |
| Spread of 5 points or more | 197 | 32.2% |
| Spread of 10 points or more | 65 | 10.6% |
| Spread of 20 points or more | 29 | 4.7% |
| Spread of 30 points or more | 10 | 1.6% |
The median spread, where one exists at all, is 5.0 percentage points. The widest is 40.5 points.
What that means in cash. A $500,000-a-year import program sitting on a 30-point spread is $150,000 a year apart from top to bottom of a single subheading. On a 5-point spread — the median — it is $25,000 a year. The same goods, the same supplier, the same port.
Subheading 6404.11 covers sports footwear with textile uppers and rubber or plastics soles. It is one subheading. Underneath it, the published general rates run from 7.5% to 48%.
90¢/pr. + 37.5% and 90¢/pr. + 20% — and are not shown on
this scale. The discriminators are the material of the upper, the material of the
outer sole, and value per pair.Read the labels again, because they are the whole point. The single largest swing in this subheading is decided by what the upper is made of: vegetable fibers at 7.5%, other textile materials at 12.5%, over half leather by external surface area at 10.5% — and everything that falls into "Other" at 37.5% or 48%.
Now consider what a supplier's invoice line usually says:
Men's canvas trainers, 1,200 pr $9.80/pr
It gives you the value. It does not tell you the fiber content of the upper, or which material has the greatest external surface area on the outer sole. The facts that decide a 40-point rate difference are not on the document the decision gets made from. Whoever classifies that shipment either knows the product physically or falls into "Other" — and "Other" is the expensive end.
Note also the two compound lines. A rate of 90¢/pr. + 37.5% cannot
be compared to a percentage at all without knowing the quantity, which is a
separate trap: software that quietly reads such a rate as "37.5%" understates the
duty on every pair.
Spreads are not evenly distributed. They cluster where the schedule distinguishes goods by physical detail — textiles, footwear, and prepared foods — rather than by function.
| Ch. | Sector | Subheadings with a spread | Median spread | Widest |
|---|---|---|---|---|
| 64 | Footwear | 24 | 24.1pp | 40.5pp |
| 62 | Apparel, not knitted | 37 | 11.0pp | 27.9pp |
| 61 | Apparel, knitted | 12 | 8.6pp | 26.4pp |
| 59 | Coated & industrial textiles | 7 | 7.5pp | 14.1pp |
| 29 | Organic chemicals | 77 | 6.5pp | 6.5pp |
| 20 | Prepared vegetables & fruit | 17 | 6.0pp | 21.1pp |
| 04 | Dairy & eggs | 17 | 5.0pp | 20.8pp |
| 85 | Electrical machinery & electronics | 23 | 3.9pp | 7.5pp |
| 96 | Miscellaneous manufactured articles | 9 | 2.9pp | 13.2pp |
| 87 | Vehicles & parts | 12 | 2.5pp | 5.5pp |
| 39 | Plastics & articles | 13 | 2.3pp | 5.3pp |
Two readings of this table, and both matter. If you import footwear or apparel, a single misplaced line is worth more than most freight negotiations. If you import machinery, electronics, or plastics, your spreads are narrow — which means classification risk in your program is mostly about trade remedies (Section 232 and Section 301) rather than about the base rate, and your attention belongs there instead.
This is the part worth being precise about, because the distinction is the whole compliance question.
You cannot choose a rate. Goods must be classified according to the General Rules of Interpretation, and the correct classification determines the duty. Selecting a cheaper sibling line for goods that do not meet its terms is a misdeclaration, and the importer of record carries that liability under 19 U.S.C. § 1592.
Tariff engineering is a different thing and it is long settled. You may change the product — before importation — so that it correctly classifies under a different line. The Supreme Court accepted the principle in Merritt v. Welsh (1881), and it has been applied consistently since. The facts have to change first; the paperwork follows them.
In practice, for a subheading with a wide spread, the questions worth asking are:
You do not need software to start. You need a list of the HTS codes your company actually imports under — your broker can export it, or it is on your entry summaries (CBP Form 7501, column 29) — and then, for each:
Sort by that last number and the list of what to investigate writes itself. For most importers it is short — the 61.4% figure is across the schedule, not across a typical program, and the majority of spreads are small.
Doing the above by hand across a few hundred codes is a week of someone's time. Vectelos does the same arithmetic automatically: every line we return carries its rate dispersion — the spread across the sibling lines the goods could not be distinguished from — alongside the duty figure, so a line with 30 points of unresolved risk is visible rather than buried under a confident-looking number. Where the spread is wide, we show the alternative lines in plain language and ask the person who actually knows the goods to confirm which one describes them.
Two things we will not claim, because they are not true of anyone in this field. Automated classification is not solved — published state-of-the-art for AI systems classifying from short commercial descriptions sits well below what a competent human achieves with the product in front of them, and we publish our own figures rather than a marketing number. What is exact is the rate data underneath: all 13,801 published rates in our engine are verified line-by-line against the USITC schedule, and re-verified on every schedule revision.
Duty is decided at the tariff line, not the subheading, and in 61.4% of US subheadings with multiple rate-bearing lines those lines disagree — by a median of 5 points and by as much as 40.5. The facts that decide which line applies are properties of the goods that rarely appear on an invoice. Pull your code list, read every sibling line, multiply the spread by your volume, and investigate the top of that list. If you import footwear or apparel, start today; if you import machinery or electronics, your money is more likely in trade remedies than in the base rate.
We parsed all 13,801 rate-bearing lines from the USITC REST export for 2026 Revision 19, grouped them by 6-digit subheading, and compared the general (MFN) ad valorem rates of sibling lines. Chapters 98 and 99 (special classification provisions and trade remedies) are excluded, as they are not base rates. Lines whose rates are specific or compound — expressed in cents per kilogram, for example, rather than as a percentage — are excluded from the spread arithmetic because they are not directly comparable to a percentage; 611 subheadings qualified. Figures are reproducible against the published schedule.
This article is general information about the US tariff schedule, not legal advice, and it is not a customs ruling. Classification determinations depend on facts specific to your goods. Vectelos is not a licensed customs broker and does not file entries. Consult a licensed customs broker or customs attorney before acting on a classification, and consider a binding ruling where the amount at stake justifies it. Rates change: the figures here are as published on 18 September 2026 and trade remedies under Section 232 and Section 301 apply on top of the base rates discussed.