The 19 August Canada tariff: what changes for Canadian-sourced products

Josh Hume · July 2026, updated 20 August 2026 · Duty Diligence

On 23 July the US published 3 proclamations under Section 338 of the Tariff Act of 1930. Together they add a 50% duty to 554 tariff lines of Canadian origin, for goods entered from 12:01 am Eastern time on 19 August 2026. I've read the proclamations and their annexes so you don't have to; this note is what I'd want to know if I were importing from Canada.

Where this stands on 20 August

The duty took effect at 12:01 a.m. eastern on 19 August and the published tariff schedule has not caught up with it. I checked at source again on the morning of the 20th: the current release is 2026 Revision 16, and heading 9903.03 still runs from .01 to .11 with none of the 5 Section 338 headings in it.

That matters if you are working a rate out by hand. Look up one of these Canadian lines in the schedule today and the number you get is 50 points short, and there is nothing on the page to tell you the rest of it exists. The proclamations are the authority on whether the duty is owed and they have not changed. Whether it is being collected at entry this week is a question for whoever files your entries, and I would ask them rather than assume it either way.

The 4 facts that matter

The deadline is customs entry, not despatch

All 3 proclamations use the same formula: the duty applies to goods entered for consumption, or withdrawn from warehouse for consumption, on or after 12:01 a.m. eastern time on 19 August 2026. Two things follow from that wording, and both catch people out.

So the date to work backwards from is the one your customs entry is filed, not the one your pallet leaves on. For sea freight that lead time has largely gone already. For road freight from Canada it is days rather than weeks, and it is worth asking your broker for the specific date rather than assuming.

What it does to a landed cost

The arithmetic is blunt. A product with a $10 unit cost picks up an extra $5.00 of duty at the border. If it sells for $25, that is 20 points of margin gone in one entry date. Products with thin margins and Canadian origin are the ones to check first.

What I would do now

If you'd rather not do this by hand, this is the job Duty Diligence does: it reads the cost, HS code and origin you already keep in Shopify, shows the effective duty and landed margin per variant, and flags the rates that move on your own catalogue. Where the published schedule is behind an action, as it is on this one today, the app marks the affected lines provisional and puts the reason on the row. The snapshot is free and needs no card.

Sources: Federal Register documents 2026-14991 (alcoholic beverages), 2026-14992 (dairy) and 2026-14997 (general goods), published 23 July 2026; new HTS headings 9903.03.12-9903.03.16 and U.S. note 51 to subchapter III of chapter 99. The checker lists were machine-read from the scanned annexes - verify against the source before acting on any single line. Informational, not customs, legal or financial advice.