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# How to look up HS and HTS codes and read official US and UK import duty rates: 6109.10 across 4 tools

When you import goods into the United States or the United Kingdom, a 6-digit Harmonized System (HS) heading is not enough to clear customs: US entries require a 10-digit Harmonized Tariff Schedule (HTS) statistical reporting number, and UK entries require a 10-digit commodity code. We tested men's knitted cotton T-shirts (`6109.10.00.12` in the US and `6109100010` in the UK) across 4 tariff lookup tools to compare official duty rates, preferential trade-agreement rates, VAT and response times.

By OpenKrill. Published 2026-10-20. Every tariff code, duty percentage and timing below comes from recorded calls to [Tariff & HS Code Duty Finder](https://tools.openkrill.app/tools/tariffs) (`https://tariffs.openkrill.app/mcp`), the US International Trade Commission REST API and the UK HM Revenue & Customs Trade Tariff API on 2026-10-20 between 06:08 and 09:43 UTC.

## The short answer

For men's knitted cotton T-shirts imported into the United States under HTS `6109.10.00.12` (*Men's (338)*, under `6109.10.00` *Of cotton*), the US general (Most-Favored-Nation) duty rate is **16.5 percent**, the special rate is **Free** for 14 trade programs (`AU, BH, CL, CO, IL, JO, KR, MA, OM, P, PA, PE, S, SG`), the column 2 rate is **90 percent**, and the reporting units are `doz.` and `kg` (excluding any US Chapter 99 Section 301 or reciprocal tariff additions). For the same garment imported into the United Kingdom under commodity code `6109100010`, the UK third-country duty is **12.00 percent**, the preferential duty for Vietnam and CPTPP members is **0.00 percent** (with proof of origin), and UK VAT is listed at **0.00 percent** (children's qualifying sizes) and **20.00 percent** (standard adult rate). You can look up both schedules without an account on the [HS Code and Tariff Duty Finder web page](https://tools.openkrill.app/tariffs), through the [Tariff & HS Code Duty Finder MCP server](https://tools.openkrill.app/tools/tariffs), or alongside the other customs workflows on [tools for importers](https://tools.openkrill.app/for/importer).

## Step 1: Find candidate HS and HTS codes from a plain description

If you only have a product description, call `find_tariff_codes` on `https://tariffs.openkrill.app/mcp` with `country: "US"` or `country: "GB"`:

```
{"method":"tools/call","params":{"name":"find_tariff_codes","arguments":{"description":"cotton t-shirts","country":"US"}}}
```

In 2,166 ms on 2026-10-20, the US search matched 681 schedule lines on `hts.usitc.gov` and returned the 8 closest US commodity candidates (5 shown below), while the same query with `country: "GB"` returned the 3 UK Trade Tariff candidates in 670 ms, each with its full parent hierarchy so lines labelled *Men's (338)* or *Women's (339)* keep their heading context:

| Schedule | Candidate code | Declarable | Description and hierarchy path | Base duty in search |
| --- | --- | --- | --- | --- |
| US HTS | `6109.10.00.04` | Yes | All-white men's or boys' cotton T-shirts, short hemmed sleeves, crew or V-neck without pockets, trim or embroidery (352) | Inherited from `6109.10.00` (16.5%) |
| US HTS | `6109.10.00` | Yes | T-shirts, singlets, tank tops and similar garments, knitted or crocheted > Of cotton | 16.5% |
| US HTS | `6109.10.00.12` | Yes | T-shirts, singlets, tank tops and similar garments, knitted or crocheted > Of cotton > Men's or boys' > Other T-shirts > Men's (338) | Inherited from `6109.10.00` (16.5%) |
| US HTS | `6109.10.00.40` | Yes | T-shirts, singlets, tank tops and similar garments, knitted or crocheted > Of cotton > Women's or girls' > Other > T-shirts > Women's (339) | Inherited from `6109.10.00` (16.5%) |
| US HTS | `6111.20.20.00` | Yes | Babies' garments and clothing accessories, knitted or crocheted > Of cotton > T-shirts, singlets and similar garments (239) | 14.9% |
| UK Trade Tariff | `6109100010` | Yes | Articles of apparel, knitted or crocheted > T-shirts, singlets and other vests > Of cotton > T-shirts | Read via `get_duty_rate` (12.00%) |
| UK Trade Tariff | `6109100090` | Yes | Articles of apparel, knitted or crocheted > T-shirts, singlets and other vests > Of cotton > Other (singlets and vests) | Read via `get_duty_rate` |
| UK Trade Tariff | `6109100000` | No | Parent subheading *Of cotton* (not declarable; goods must use `6109100010` or `6109100090`) | Subheading only |

## Step 2: Read the US and UK duty rates for the 10-digit code

Once you pick a candidate code, pass it to `get_duty_rate` to read the exact customs duty, special or preferential trade rates, and reporting units:

```
{"method":"tools/call","params":{"name":"get_duty_rate","arguments":{"code":"6109.10.00.12","country":"US"}}}
```

For the United States, `get_duty_rate` automatically resolves the 8-digit rate parent (`6109.10.00`) when the 10-digit line (`6109.10.00.12`) is a statistical suffix, returning `general: "16.5%"`, `special: "Free (AU,BH,CL,CO,IL,JO,KR,MA,OM,P,PA,PE,S,SG)"`, `columnTwo: "90%"` and units `["doz.", "kg"]` in 2,741 ms. For the United Kingdom, you can also pass `originCountry` (such as `"VN"` for Vietnam):

```
{"method":"tools/call","params":{"name":"get_duty_rate","arguments":{"code":"6109100010","country":"GB","originCountry":"VN"}}}
```

In 511 ms, the UK lookup returned `thirdCountry: "12.00%"`, two preferential zero-duty lines for Vietnam (`CPTPP All Members: 0.00%` and bilateral `Vietnam: 0.00%`, when rules of origin and proof of origin are met), `vat: ["0.00%", "20.00%"]`, and `otherMeasures: ["Supplementary unit"]`.

## How 4 tariff tools compared on HTS 6109.10.00.12

We ran the same men's cotton T-shirt lookup against 3 competing tariff tools on 2026-10-20 (also summarized on our [HS code and tariff tools comparison page](https://tools.openkrill.app/compare/hs-code-tariff-tools)):

| Tool | Result on 6109.10.00.12 | Wall time | Setup | Score |
| --- | --- | --- | --- | --- |
| **OpenKrill Tariff & HS Code Duty Finder** | 16.5% general, Free special (14 FTA codes), 90% column 2, units `doz., kg`, full 4-level heading path, USITC source and Chapter 99 caveat | 2,741 ms | None (web page or remote MCP) | 9.1 / 10 |
| **tariff-resolver** (`opsloft/tariff-resolver` npm MCP) | 16.5% base MFN, special, 90% column 2, MPF fee and Chapter 99 layers (12.5% Vietnam adder), but mixed in unrelated heuristic layers such as quartz surface goods | 2,789 ms (2,759 ms startup + 30 ms call) | Local `npx` package install | 8.7 / 10 |
| **Dutiable** (`dutiable.io`) | Category page listed 8-digit `6109.10.00` at 16.5% US, 12% EU and 12% UK; direct `/hts/6109.10.00.12` URL returned HTTP 404, and no special or column 2 rates were shown | 2,333 ms | Multi-page browser navigation | 7.7 / 10 |
| **Accio HS Code Lookup** (`accio.com`) | 6-digit `6109.10` only; prose stated 16.5% base US duty, but its summary table showed 34% US (assuming Chinese Section 301 origin) and 0% UK (actual UK third-country duty is 12.00%) | 1,638 ms | Browser form required for custom codes | 7.6 / 10 |

## How to connect the MCP server to your AI client

Point any MCP-compatible assistant at `https://tariffs.openkrill.app/mcp`, or follow the step-by-step install guides for [Tariff & HS Code Duty Finder in ChatGPT](https://tools.openkrill.app/integrations/tariffs/chatgpt), [Tariff & HS Code Duty Finder in Claude](https://tools.openkrill.app/integrations/tariffs/claude), [Tariff & HS Code Duty Finder in Cursor](https://tools.openkrill.app/integrations/tariffs/cursor) and [Tariff & HS Code Duty Finder in Pi](https://tools.openkrill.app/integrations/tariffs/pi).

## Mistakes to avoid when looking up tariff codes

- **Declaring a non-declarable 6-digit or 8-digit heading.** In the UK schedule, `6109100000` (*Of cotton*) carries `declarable: false`; customs entries must use a 10-digit declarable leaf such as `6109100010`.
- **Forgetting US Chapter 99 additional duties.** The 16.5 percent rate on `6109.10.00.12` is the Chapter 61 base rate. Goods from certain origins face additional duties under Chapter 99 (such as Section 301 or IEEPA reciprocal tariffs) that stack on top of the base rate.
- **Assuming a preferential 0.00 percent rate applies automatically.** Under UK-Vietnam and CPTPP rules, the 0.00 percent preferential rate on `6109100010` requires valid proof of origin and compliance with yarn-forward or double-transformation rules of origin.
- **Treating a search match as a binding customs classification.** Only a CBP binding ruling in the US or an HMRC Advance Tariff Ruling in the UK legally binds customs.

## Frequently asked questions

### What is the US import duty rate for a given HTS code, like 6109.10.00.12?

Under the US Harmonized Tariff Schedule (hts.usitc.gov), HTS 6109.10.00.12 (men's knitted or crocheted cotton T-shirts) inherits its rate from the 8-digit subheading 6109.10.00: a 16.5 percent general (MFN) duty rate, a Free special rate for qualifying goods under 14 trade programs (AU, BH, CL, CO, IL, JO, KR, MA, OM, P, PA, PE, S, SG), and a 90 percent column 2 rate, reported in dozens and kilograms. Additional Chapter 99 duties depend on the country of origin.

### Which HS code should I use for men's cotton T-shirts, and what duty will I pay in the US and UK?

All countries share the 6-digit HS subheading 6109.10 for knitted or crocheted cotton T-shirts. In the United States, standard men's cotton T-shirts use 10-digit HTS 6109.10.00.12 (or 6109.10.00.04 for all-white crew or V-neck undershirts) at a 16.5 percent base general duty rate. In the United Kingdom, cotton T-shirts use 10-digit commodity code 6109100010 at a 12.00 percent third-country duty rate (or 0.00 percent preferential duty from qualifying FTA partners such as Vietnam) plus 20.00 percent standard VAT on adult sizes.

### Is there a free tool or API that gives official tariff rates by HS code without an account?

Yes. OpenKrill's Tariff & HS Code Duty Finder offers both a free web lookup at tools.openkrill.app/tariffs and a keyless MCP server at https://tariffs.openkrill.app/mcp (up to 60 calls a minute per network). It queries the live US International Trade Commission (hts.usitc.gov) and UK HMRC Trade Tariff (trade-tariff.service.gov.uk) schedules directly.

### Does get_duty_rate include US Chapter 99 Section 301 or Section 232 tariffs?

No. For US codes, get_duty_rate returns the Chapter 1 to 97 schedule rate (general, special and column 2) and reminds you in its notes that additional duties under Chapter 99 (such as Section 232, Section 301 or other trade remedies) are not included and must be checked for the origin country.

## Sources

- US and UK tariff lookup runs: [Tariff & HS Code Duty Finder MCP server](https://tools.openkrill.app/tools/tariffs) (`https://tariffs.openkrill.app/mcp`) and [web tool](https://tools.openkrill.app/tariffs), recorded on 2026-10-20 between 06:08 and 09:43 UTC.
- United States tariff schedule: [US International Trade Commission Harmonized Tariff Schedule (hts.usitc.gov)](https://hts.usitc.gov/reststop/search?keyword=6109.10.00), read on 2026-10-20.
- United Kingdom tariff schedule: [UK Trade Tariff API (trade-tariff.service.gov.uk)](https://www.trade-tariff.service.gov.uk/api/v2/commodities/6109100010), published by HM Revenue & Customs, read on 2026-10-20.
- Competitor benchmarks: [opsloft/tariff-resolver](https://github.com/opsloft/tariff-resolver), [Dutiable](https://dutiable.io/hs-code/clothing-apparel) and [Accio HS Code Lookup](https://www.accio.com/wow/tool-hs-code-lookup.html), tested on 2026-10-20.