Getting your product classification codes right is one of the most important, and most misunderstood, parts of the import process. The Harmonized Tariff Schedule (HTS) determines everything from duties and taxes to admissibility and trade compliance, yet even experienced importers make errors that can lead to costly penalties, delays, and audits.

Here are the 10 most common HTS classification mistakes, and how you can avoid them.

1. Relying on Guesswork to Classify Goods

Too often, importers classify goods based on what they think something is, rather than what it actually is. HTS classification depends on a product’s composition, function, and form, not just its common name. Providing your customs broker with incomplete or overly broad descriptions can easily lead to errors. Always gather detailed product specs, including materials, functions, and design details, before confirming your HTS code.

2. Copying Someone Else’s Classification

A competitor or supplier using a certain HTS code doesn’t mean it’s accurate for your product. Products that appear similar on the surface can differ in material, functionality, or intended use—all of which can change classification. Be sure to independently verify each classification against the official HTS and your product’s technical make-up.

3. Ignoring the General Rules of Interpretation (GRIs)

The GRIs, rules that govern how to apply product classifications within the HTS, are the foundation of classification. Many importers skip them entirely, treating the HTS like a searchable catalog instead of a structured legal document. Understanding how the GRIs work ensures your code selection stands up to scrutiny from U.S. Customs and Border Protection (CBP).
A common mistake is jumping down to GRI 3(c) and applying the “last numerical” rule before testing the preceding GRI.

4. Misclassifying Kits and Sets

When products ship together as sets, determining the correct HTS code can be tricky. CBP describes the rules for determining if you have a set for classification purposes: 1) The items must be seemingly have different unique HTS, 2) The items in the set must be packaged together at time of import - ready for retail sale, and 3) The items need to carry out a particular activity, or meet a particular need.

Only when all three criteria are met may the entire set be classified under the HTS of the item which gives the whole its “essential character."

5. Using Outdated HTS Codes

The Harmonized Tariff Schedule is updated frequently, at least twice per year. Using an obsolete code can result in entry rejections or miscalculated duties. Always check for revisions, especially if your products fall under categories affected by new trade actions or tariff changes. The Flexport Tariff Simulator is updated in real time, featuring the last updated date for each HTS code.

6. Overlooking Country-Specific Differences

The U.S. HTS is not the same as other countries’ tariff schedules. Importers frequently use their foreign manufacturer’s or vendor’s classification code without realizing it doesn’t apply to U.S. imports. Always confirm your classification using the U.S. Harmonized Tariff Schedule (HTSUS).

7. Failing to Work With an HTS Classification Expert

One of the costliest mistakes made by importers is trying to handle every classification decision in house, without first consulting a licensed customs expert or trade compliance specialist. HTS interpretation often requires experience, legal knowledge, in the context of binding pre-entry classification decisions.

Flexport’s trade advisory experts help importers and exporters simplify trade compliance by analyzing product details and materials, assigning accurate codes for every market, maintaining audit-ready classification records, and keeping businesses informed about any changes to classification from both CBP and the World Customs Organization.

8. Not Documenting Classification Rationale

If CBP questions your classification, you must be able to show how you arrived at it. Without documentation like product data, HTS notes, or ruling references, you could owe back duties or face fines.

9. Overlooking Customs Rulings and Precedents

CBP regularly issues binding rulings that can clarify classification for specific products. Ignoring this database means missing out on valuable precedents and guidance that could simplify your compliance process.

10. Neglecting to Review Classifications Over Time

Products change. New materials, features, and designs can all impact HTS classification. Reviewing your classifications annually or whenever your product specs change can help maintain compliance while preventing costly surprises.

HTS classification isn’t just a paperwork step: it’s a crucial part of trade compliance that directly impacts your applicable duties, landed costs, and speed to market. Getting it wrong can mean delays, penalties, or overpaid duties.

Partnering with Flexport helps importers avoid these pitfalls with expert classification support, industry-leading technology, and the latest guidance on nuanced regulatory changes. By letting Flexport handle the complexities, your team can stay focused on moving goods faster, staying compliant, and protecting your bottom line.