Your package has been held up at the border for six days. The contents are completely legal, the commercial invoice is filled out, and the value is correct. The problem comes down to six digits: the HS code What you entered does not match what's in the box.

This is one of the most common reasons for customs delays—and one of the least understood by Canadian small and medium-sized businesses. The HS code does more than just describe the goods: it determines the duty rate, eligibility for trade agreements, required permits, and how quickly your shipment crosses the border.

Here's how tariff classification actually works in 2026, where the pitfalls lie, and how to build a reliable list of codes for your catalog.

What an HS Code Is, in Practice

HS stands for «Harmonized System,» the World Customs Organization’s nomenclature used by more than 200 countries and territories. It has a nested structure:

• The first 6 digits are universal. The same product has the same six-digit number in Canada, the United States, Germany, and Japan.
• The following figures are national. In Canada, the complete tariff classification number for the Customs Tariff consists of 10 digits: 6 international digits, 2 Canadian digits, and 2 statistical digits.
• Each destination country has its own. The U.S. code (HTSUS) also has 10 digits, but beyond the sixth digit, it does not necessarily correspond to the Canadian code.

In practice: On a mail declaration or a commercial invoice, the first six digits are almost always sufficient. For a commercial import declared to the CBSA, the 10-digit number is required.

Why Poor Code Is Expensive

The most costly issue isn't the penalty—it's the incorrect code that was used repeatedly for two years on thousands of mailings. The correction must then be applied retroactively for the entire period.

The Six Most Common Mistakes

1. Organize by use rather than by material

The general rule is based on the premise that the goods is, not what it's used for. An aluminum phone stand is classified as an aluminum product, not as a phone accessory. This is counterintuitive, and it's the number one source of error.

2. Enter the supplier code

The code that your Asian or European supplier used for export is valid for that country. The first six digits are generally transferable; the last four are not. Copying an 8- or 10-digit code from another country results in a number that does not exist in the Canadian Tariff.

3. Ignore sets and composite items

A gift set containing three different products is not listed on three separate lines. The general rules of interpretation stipulate that a retail assortment is classified according to the item that defines its essential character.

4. Write a description that contradicts the code

«Parts» or «samples» on a commercial invoice almost guarantee that the shipment will be inspected. The plain-language description and the code must convey the same information: material, function, and condition.

5. Never study

The HS nomenclature is revised periodically, and the Canadian Customs Tariff is published annually. Some headings are eliminated, while others are split. A code that was correct in 2022 may no longer exist today.

6. Handle samples and gifts separately

Even a shipment with no commercial value must still be classified. «Gift» is not a classification.

How to Find the Right Code

1. Describe the merchandise in a factual sentence. Main ingredient, function, degree of processing, presentation. Don't sell the product—describe it.
2. Start with the chapter, not the search engine. The Customs Tariff is organized by material and then by degree of processing. Identifying the correct chapter eliminates 95 % of false leads.
3. Read the section and chapter notes. These are the ones that resolve most borderline cases, and they have the force of law.
4. Apply the general rules of interpretation in order. Rule 1 (wording of positions and notes) covers the vast majority of cases.
5. Check with the destination country to ensure the logic is correct. Confirm that the six-digit position also appears in the rate; if it is missing, this indicates an error.
6. Document your reasoning. A one-line note for each SKU explaining why that code was chosen is very helpful during an audit.

Advance Ruling: Your Safety Net

When a product is truly ambiguous, or when it accounts for a significant volume, the CBSA issues advance decisions with respect to tariff classification. You submit a detailed description and, if applicable, a sample; the Agency issues a written decision that is binding on the CBSA.

Two things to know: Processing generally takes about 120 days from the time the CBSA has all the necessary information, and the decision must be requested before importation. This is not a troubleshooting tool; it’s a planning tool—intended only for high-volume SKUs or those with disputed classifications.

Creating a list of codes for your catalog

For an SME that regularly ships internationally, the real benefit isn’t just tracking a package—it’s never having to think about it again.

• Add an «HS code» field to your product listing, just like weight and dimensions. It is then automatically transferred to the labels and declarations.
• Start with your 20 most-shipped SKUs. They generally account for the bulk of cross-border trade.
• Be sure to note the country of origin at the same time. Classification and origin are the two factors that determine rights; one without the other is meaningless.
• Review the list once a year, upon the publication of the new Customs Tariff.
• Have your customs broker review the borderline cases. That's exactly what you're paying him for, and asking a question before the work is sent costs infinitely less than having it revised afterward.

Key Takeaways

The HS code is the most critical piece of information in your export documentation—and the one most often filled in based on guesswork. Six well-chosen digits, backed by a consistent description and documented origin, eliminate the majority of customs holds and unexpected duties.

The rules described here are general in nature: classification depends on the specific characteristics of each good, and duty rates vary depending on the country of origin and applicable agreements. For significant cases, verify with the CBSA or a licensed customs broker.

Do you regularly ship internationally? Compare rates and services on Expert Shipping and get your packages across the border without any unpleasant surprises.