Guides
Import duty, HS codes and tariffs — explained plainly
Sourced, jargon-free guides to classifying products, reading the tariff schedule, and calculating the real landed cost. Every rate we quote links back to the official schedule of record.
The $800 de-minimis rule — what changed in 2025–26
De minimis let low-value shipments enter the US duty-free and with minimal paperwork. In 2025–26 that changed dramatically, and is now suspended for every origin. Here's what the rule was, what the exemption covered, and how the changes affect anyone importing small parcels.
July 6, 2026 · 6 min read
How to find the HS code for your product
A step-by-step, plain-English method for classifying any product to the correct HS/HTS code — how the schedule is structured, how to read a heading, and the mistakes that lead to overpaid duty or a CBP penalty.
July 6, 2026 · 9 min read
Import duty from China to the USA in 2026 (Section 301 explained)
What actually goes into the duty on Chinese goods: the base HTS rate, the Section 301 additional tariffs by list, and the newer reciprocal measures. How the layers stack, why the number keeps moving, and how to find your product's real rate.
June 24, 2026 · 8 min read
What is landed cost and how to calculate it
Landed cost is the true, all-in cost of getting a product to your door — product, freight, insurance, duty and customs fees. Here's every component, a worked formula, and the hidden fees that wreck margins when you forget them.
June 10, 2026 · 7 min read
Harmonized Tariff Schedule (HTS) — a plain-English guide
The HTS is the official list of every product the US imports and the duty on each. Here's how it's structured — sections, chapters, headings and the 10-digit line — how to read a duty rate, and how Column 1 and Column 2 differ.
May 14, 2026 · 8 min read
How US import duty is calculated (with a worked example)
Import duty isn't one number — it's a stack. This walks through the exact calculation from customs value to the final bill, with a real worked example including base duty, Section 301, MPF and HMF.
April 30, 2026 · 7 min read
MPF and HMF: the customs fees importers forget
Beyond duty, US Customs charges two fees on most imports: the Merchandise Processing Fee and the Harbor Maintenance Fee. Here's exactly what each is, how it's calculated, the annual min/max, and when each one applies.
April 16, 2026 · 5 min read
Section 232 steel & aluminum tariffs explained
Section 232 lets the US impose tariffs on imports it deems a national-security risk — most famously steel and aluminum. Here's how the measure works, what it covers, and why derivative products get caught too.
April 2, 2026 · 6 min read
How AI agents can classify products and compute landed cost
A guide for developers and AI agents: how to turn a product description into an HS/HTS code and a full landed-cost estimate programmatically, using PortRobin's public API and MCP server — with the honesty rules that keep the numbers trustworthy.
March 19, 2026 · 7 min read
HS code vs HTS code vs Schedule B — the difference
HS, HTS and Schedule B are three related but distinct product codes, and using the wrong one causes real problems. Here's what each is for, how they overlap, and which one you need for imports versus exports.
March 5, 2026 · 6 min read
How to avoid overpaying import duty
Most importers overpay duty not through fraud but through inertia — a stale classification, a missed free-trade program, an unclaimed refund. Here are the legitimate ways to make sure you pay the right rate and not a cent more.
February 19, 2026 · 7 min read
Country of origin: why it decides your tariff
Origin — not where you bought the goods or where they shipped from — determines which additional tariffs apply. Here's how customs determines country of origin, what substantial transformation means, and why it's the highest-stakes call in importing.
February 5, 2026 · 6 min read
Classify a product and see its real duty
Describe any product to get its HS/HTS code with the reasoning, the sourced duty rate including Section 301 and 232, and the full landed cost.