Visualize how multiple U.S. tariff layers — base MFN duty, Section 301, Section 232, and the new Section 338 duty on Canadian goods — compound on a single import shipment. Enter your product value and toggle each tariff section to see the stacking effect.
See how multiple tariff layers compound on a single import shipment. Toggle each section on or off to visualize the stacking effect on your landed cost.
Enter the base MFN duty rate for your HTS code. Ranges from 0% (most electronics) to 37.5%+ (apparel, textiles).
At 5.0% effective rate, your duty exposure is within a typical range. Ensure your HTS classification is accurate to avoid overpayment.
Cargo in a CBP-bonded warehouse owes no duty until it's withdrawn for consumption — that defers cash outlay for up to 5 years and lets you re-export without ever paying the U.S. stack. One honest caveat: deferral is not a rate lock. Duty is assessed at the rate in effect on the withdrawal date, so bonded storage does not shield covered Canadian goods from the Section 338 50% layer. C&C Warehouse is a bonded & General Order facility minutes from the Port of Charleston — tell us your cargo profile and the operator (not a call center) replies within one business day.
C&C Warehouse is operated by FreightFigures' publisher. candcwarehouse.com
The Most-Favored-Nation rate is the baseline U.S. import duty determined by your product's HTS code. Every country gets this rate unless an FTA (like USMCA) provides a zero or reduced rate. Rates range from 0% on electronics to over 30% on apparel and textiles.
Authorized under Section 301 of the Trade Act of 1974, these tariffs apply only to goods manufactured in China. Lists 1–3 (industrial goods) carry 25%. List 4A (consumer goods) carries 7.5%. List 4B was suspended. These stack on top of the base MFN rate.
National security tariffs under the Trade Expansion Act of 1962. As of March 2025, steel and aluminum imports face a 50% tariff from all countries with no exemptions. Canada and Mexico are NOT exempt despite USMCA. This is one of the highest individual tariff layers.
A 10% universal import surcharge that was in force February 24 – July 24, 2026 under Section 122 of the Trade Act of 1974 (an announced increase to the 15% statutory maximum was never implemented). It replaced the IEEPA reciprocal tariffs after the Supreme Court ruling and lapsed at its 150-day statutory sunset, 12:01 a.m. EDT on July 24, 2026. It no longer applies to new entries — use this layer only when reconstructing an entry filed inside that window.
A 50% additional ad valorem duty on specified Canadian-origin goods under Section 338 of the Tariff Act of 1930 — a provision never previously used to impose duties. Live since 12:01 a.m. ET August 19, 2026 from three proclamations signed July 20, 2026, covering categories such as motor vehicles, dairy, alcoholic beverages, furniture, cement, paper, textiles, cosmetics and sporting goods. USMCA preference does not exempt covered goods. Articles already subject to a Section 232 action (steel, aluminum, autos and parts, lumber), plus energy and potash, are carved out. There is no statutory sunset.
HTS basics, current duty ranges, Section 301/232 status, MPF/HMF math, and the full landed-cost formula — in one free reference.
U.S. import tariffs are additive, not multiplicative. Each tariff layer is calculated as a percentage of the original declared customs value. For a $10,000 shipment of steel from China:
A second worked example, live since August 19, 2026: $40,000 of Canadian-origin furniture takes 0% MFN under USMCA — but Section 338 adds 50% ($20,000) anyway, because USMCA preference does not exempt covered goods. The same cargo sitting in a bonded warehouse since July owes the 50% on withdrawal for consumption, because duty is assessed at the rate in effect on the withdrawal date, not the date it was stored.
That's why understanding tariff stacking is critical — a single product can face an effective duty rate of 80%+ when all layers apply. Use our Duty & Tariff Calculator for product-specific rates, or read our Tariff Stacking Guide for strategies to reduce exposure. Canadian-origin importers should start with the full Section 338 product list.
Common questions about tariff stacking and compound duty rates
Tariff stacking refers to the cumulative effect of multiple tariff layers applied to a single import shipment. For example, steel imported from China can face a base MFN duty, plus Section 301 tariffs (25%), plus Section 232 tariffs (50%) — all stacking on the same customs value, for an effective rate near 80%. Covered Canadian-origin goods face an additional 50% Section 338 layer on top of their base duty (in effect since 12:01 a.m. ET August 22, 2026, after U.S.–Canada talks collapsed), and USMCA preference does not exempt them.
U.S. tariff layers are additive, not multiplicative. Each layer is calculated as a percentage of the declared customs value. So a $10,000 shipment with 5% MFN + 25% Section 301 = 30% effective rate = $3,000 total duty. All layers apply to the original product value, not compounded on top of previous layers.
As of August 2026, Chinese imports face up to three tariff layers: base MFN duty (varies by HTS code), Section 301 tariffs (25% for Lists 1–3, 7.5% for List 4A), and Section 232 tariffs (50% on steel and aluminum). The Section 122 universal 10% surcharge expired on July 24, 2026 and no longer applies. For steel from China, the combined rate can still approach 80%.
All U.S. tariff layers are calculated on the original declared customs value (ad valorem), not compounded. A $10,000 item with 5% MFN and 25% Section 301 pays $500 + $2,500 = $3,000, not $500 + $2,625 (which would be the compounded amount). You can simply sum the percentages to get the effective rate.
Strategies include: sourcing from FTA partner countries, using Foreign Trade Zones (FTZs) for duty deferral, bonded warehouse storage, first-sale valuation to lower customs value, and reviewing HTS classification to ensure accurate duty rates. Two important limits: USMCA preference does not exempt goods covered by Section 338, and bonded storage defers duty rather than locking a rate — duty is assessed at the rate in effect on the withdrawal date. A licensed customs broker can advise on the best strategy.
Duty on warehoused cargo is assessed at the rate in effect on the withdrawal date - so goods held under bond float on the stack instead of locking it in, for up to 5 years. C&C Warehouse is a CBP-bonded & General Order facility minutes from the Port of Charleston. Tell us your cargo profile and the operator replies within one business day.
C&C Warehouse is operated by FreightFigures' publisher. candcwarehouse.com
Our partner network includes U.S. Customs Bonded warehouses, climate-controlled facilities, and full-service 3PLs across the Southeast.