You can find your own duty before you ever call a broker — and you should, because it drives your landed cost and your sourcing decision. Here's how to research the full stack yourself, and where to stop and get help.
Step 1: Find Your HTS Code
Classification determines everything downstream. The official HTS (Harmonized Tariff Schedule) is published by the USITC (US International Trade Commission) and is free to search online at https://hts.usitc.gov — where you can also download the full schedule and individual chapters as PDF files at https://hts.usitc.gov/download. Describe your product precisely — material, function, how it's made — and work down through chapter, heading, and subheading. Getting the code right is the hard part, and the part worth slowing down on. (See HTS Code Basics.) To see how CBP has actually classified products like yours, search its published rulings — see How to Search CBP's CROSS Rulings Database.
Step 2: Read the Base Duty Rate
Your subheading lists the "General" (most-favored-nation) rate. That's your base — the floor of the stack.
Step 3: Check for Additional Tariffs by Origin
Now check whether your HTS code and country of origin appear on the additional-tariff programs: Section 301 actions (published by the USTR — US Trade Representative, https://ustr.gov), Section 232, and any AD/CVD (antidumping and countervailing duty) orders. This is where the base rate and the real rate diverge. (For how to check a Section 301 tariff and what to review with your broker, see Section 301 Tariffs: The Process to Review With Your Customs Broker; for Section 232, see Section 232 Tariffs: The Process to Review With Your Customs Broker; for AD/CVD, see AD/CVD Duties: The Process to Review With Your Customs Broker.)
Step 4: Add It Up
Total duty rate = base + every applicable additional tariff. Multiply by your customs value to estimate the duty owed. Now you have a real landed-cost input instead of a guess.
Step 5: Confirm When It's High-Stakes
When classification is ambiguous or the money is significant, confirm with a licensed customs broker, or request a binding ruling from CBP (Customs and Border Protection) — a written determination you can rely on. You submit a binding ruling request through CBP's eRulings portal at https://erulings.cbp.gov/s/.
One Caveat
What you find today is a snapshot. Rates, lists, and exclusions change — which is exactly why researching once isn't enough, and monitoring is its own discipline. (See How to Stay Ahead of Tariff Changes.)
This is general guidance, not legal advice. Classification is fact-specific and consequential — verify your HTS code and duty with a licensed customs broker before relying on it.
Do you look up your own HTS code and duty before sourcing a product, or take the factory's or forwarder's word for it? We'd like to hear how you research a tariff.