Why did my import duty go up when I changed the fabric?
Rates on this page, and when they were read: the two duty rates below were read from the US Harmonized Tariff Schedule on 17 August 2026. Duty rates move. Every perishable fact on this page is a rate, and every rate carries that date — the mechanism does not change when a rate does, so the reasoning stays correct even after a number stops being. Check any figure against hts.usitc.gov, which is public and free, before you rely on it.
Because duty is charged on what a product is made of, not what it is. On the rates read 17 August 2026, a cotton t-shirt entering the United States was dutiable at 16.5% and the same t-shirt in man-made fibre at 32%. Switching fabric can nearly double your duty without changing anything a customer would notice.
The two codes doing the damage
Every product crossing a border gets a classification code. T-shirts split by fibre:
| What it is made of | Code | Duty rate |
|---|---|---|
| Cotton, knitted | 6109.10.00 | 16.5% |
| Man-made fibre, knitted | 6109.90.10 | 32% |
Source: US Harmonized Tariff Schedule, hts.usitc.gov. These are public and free to look up. Both rates read 17 August 2026.
What that costs, in actual money
The rate applies to the customs value of the goods — roughly what you paid your supplier, not what you sell it for.
| Order value | Cotton at 16.5% | Man-made fibre at 32% | Difference |
|---|---|---|---|
| $500,000 | $82,500 | $160,000 | $77,500 |
| $30,000,000 | $4,950,000 | $9,600,000 | $4,650,000 |
Same shirts. Same supplier. Same order quantity. The fibre changed.
These are the HTS general rates, and they are not your whole bill.
Additional duties under HTSUS Chapter 99 — Section 301 headings in the 9903.88 series,
Section 232 headings — stack on top of the rate in your product's own subheading, and which of
them apply is driven by the goods' origin rather than by their fibre. Chapter 99 is published
alongside the rest of the schedule at hts.usitc.gov.
Cotton (6109.10.00) and man-made fibre (6109.90.10) are separate subheadings and
are treated separately for this purpose, so check the Chapter 99 position of both rather
than assuming the difference above is your whole exposure. The stacking mechanism,
and why origin is decided separately from the label, is set out in
the country-of-origin page.
Why nobody catches it
The fabric decision gets made in a product or sourcing conversation — better margin, better feel, the supplier had it in stock. It does not feel like a customs decision, so nobody routes it past anyone who thinks about duty. The bill arrives months later, at the border, in a different part of the business, and by then it is an entry that has already been filed.
This is why the expensive classification mistakes are almost never the complicated ones. They are ordinary product changes that no one thought to re-check.
What to actually check
- Any product where the material changed this year. Fabric, alloy, plastic type, coating — all of them can move the code.
- Blends specifically. A garment's classification usually follows the fibre that makes up the majority by weight, so a 50/50 blend sits on a cliff edge: a small formulation change flips the rate.
- Whether anyone re-classified after the change, or whether the old code just carried forward on the paperwork because it always had. This is the common case.
- Chapter 61 against Chapter 62 — knitted against woven — if the construction changed and not just the fibre. That is a different split with its own rates.
The honest boundary
This page explains the mechanism so you know whether you have a problem. It is not legal or customs advice, and classification genuinely has hard cases: composite goods, sets, and anything where the essential character is arguable are worth a licensed customs broker's opinion, not a web page's. What a page like this can do is stop you from finding out at liquidation.
Sourcerra holds 34,817 US and UK tariff rates read from official customs sources (counted 22 August 2026), and tracks US tariff rule changes against the Federal Register. A fabric swap is your decision, not a rule change — nothing alerts you to it. What the rate data does is let you price both codes before you commit, instead of finding out at liquidation. Every figure above can be checked against the primary source linked beside it. If you find something here that is wrong, it will be corrected and the correction dated.