Why Your Shopify Checkout Is Charging the Wrong Duties

A merchant ships an order from Toronto to a customer in Ohio. Checkout collected eleven dollars in duty. The carrier invoice arrives three weeks later at fifty-four. Nobody changed a setting. This is the most common cross border problem we see right now, and after the tariff changes of August and September 2026 it is getting worse. Here is why it happens and what to fix.

All Shopify behaviour below is quoted from its own documentation, checked on 20 September 2026.

Why is your checkout charging the wrong duty?

Because the number at checkout is an estimate produced from data you supplied, not a quote from customs. Shopify calculates it from the HS code and country of origin on each product. If either is wrong, missing or out of date, the calculation is wrong, and the failure is silent.

Three things then compound it. Tariff rates changed twice in the last month. Customs may classify your product differently from the code you entered. And the amount your carrier bills you is set at the border, long after the customer has paid.

Why does checkout show zero duties?

Usually one of three causes, and the first one is the one merchants miss.

• Missing or wrong HS codes. Shopify's troubleshooting documentation states: "If inaccurate HS codes are entered for products or if HS codes are missing, then it might prevent duties and import taxes from being applied to the order at checkout." Note what that means in practice. Checkout does not warn you. It simply charges nothing.
• Below the de minimis threshold. "If an order is below the de minimis threshold for a country or region and you're not registered to collect taxes in that country or region, then the order isn't subject to duties and import tax."
• Registration not entered. If you are registered to collect tax in the destination but have not entered that registration in Shopify, taxes on orders below de minimis are not calculated.

For US-bound parcels, the second reason mostly no longer applies, and that is the change most stores have not absorbed.

What changed in 2026 that broke settings that used to work?

Three things, in order of how badly they hurt a Canada to US route:

1. The US de minimis exemption is gone. Duty free treatment for shipments under US$800 was suspended from 29 August 2025, continued by executive order in February 2026, and written into regulation through customs rules published on 24 June 2026. Low value parcels that once crossed free are now dutiable.
2. Section 338 duties of 50% on listed Canadian goods, effective 22 August 2026. The critical detail: a USMCA claim does not exempt covered goods. If your product's classification is on the list, the 50% applies on top of the ordinary rate.
3. Canada's counter-tariffs from 8 September 2026, matching US rates on C$27.6 billion of US goods, covering steel, dairy, appliances, agricultural equipment, pulp and paper and electronics. This hits your landed cost on US-sourced inventory, not just your outbound orders.

Any duty configuration built before August 2026 is now working from a different world. That is not a Shopify fault, it is a rate environment that moved twice in a month.

Why does the carrier bill differ from what you collected?

Shopify names the causes directly. Customs authorities "might apply HS codes to your products that differ from the codes that were used to calculate duties and import tax." If the prices on your commercial invoice do not match what you charged the customer, "the carrier might have incorrect pricing information." Currency movement between checkout and clearance adds the rest.

The practical consequence: your commercial invoice and your checkout must agree on classification, origin, price and quantity. When they disagree, you eat the difference, and at 50% tariff rates that difference is no longer a rounding error.

Where do you set HS codes and country of origin?

Per Shopify's HS code documentation, go to Products, select the product, and in the Shipping section set the Country of origin and the Harmonized System (HS) code. You can also edit customs information while buying a label from an order.

For a catalogue of any size, do it in bulk: Products, select items, Bulk edit, Columns, Shipping, then the harmonized system code column. Shopify's guidance is blunt about why this matters, citing "non-compliance penalties, border delays, seizure of the products, or denial of import".

Country of origin means where the product was made, not where you ship it from. Getting this wrong on Canadian-made goods is now a 50% mistake.

One more field decides whether any of this works: product category. Shopify uses its standard product taxonomy alongside the HS code, and a product left in a vague category inherits a vague classification. If you imported your catalogue from another platform, check a sample now rather than after a customs bill arrives.

What can Shopify's duty collection not do?

These limits are documented, and each one has bitten a real store:

Is Managed Markets the answer?

It can be, and it is now available to Canadian merchants. Shopify's July 2026 announcement put the guarantee plainly: "Import tax and duty collection is guaranteed - you'll never receive an adjustment." It also brings duties-inclusive pricing for international buyers, daily payouts in CAD, and discounted DHL Express and FedEx labels bought inside the admin.

The requirements are specific. Your store must use Shopify Payments. Your store currency must match your home country's default currency. You need at least one non PO box business location and a fulfilment location in the operating country, and Canadian merchants with several fulfilment locations must have them in the same province. Canada also requires Shopify Tax or Basic Tax settings.

Shopify's requirements page does not publish the fee, so check the current rate in your admin before committing. The trade is straightforward: you pay a percentage to move the accuracy risk off your own books. At today's tariff volatility, that trade is more attractive than it was a year ago.

How do you test this properly?

Do not trust a settings screen. Test the route.

1. Place a real test order on your worst case route, Canada to US, with a product you actually sell.
2. Record the duty charged at checkout, then compare it against the carrier invoice when it arrives. That gap is your exposure per order.
3. Audit twenty SKUs for HS code and country of origin accuracy, prioritising your top sellers and anything Canadian-made.
4. Re-test after every tariff change. Two dates moved rates in the last month alone.
5. Check your commercial invoice output matches checkout on price, quantity, classification and origin.

Merchants have been reporting these symptoms publicly for a year. One Shopify Community thread from August 2025 describes a Canada to US checkout still calculating at 6.8% after rates rose. Another from October 2025 shows duty on the same item dropping from US$5.46 to US$2.79 with no configuration change. The pattern is not new; the cost of ignoring it is.

What we fix when a store has this problem

The work is usually four things: a catalogue-wide HS code and origin audit, duty settings rebuilt per market, commercial invoice output aligned with checkout, and a test protocol somebody runs after each rate change. On a mid-sized catalogue that is days, not weeks, and it pays for itself on a single month of misquoted parcels.

For the wider picture on what changed in these markets this year, see our breakdown of US and Canada ecommerce data for 2026, and our guide to Shopify Markets for cross-border selling.

Get your duty setup checked

Free review. Email hello@exactwhy.com with subject "Duties" and tell us your store URL, which routes you ship, and one recent order where the carrier bill differed from checkout. We respond within 4 hours with what is misconfigured and what it is costing you per order.

Prefer a form? Send it through the contact page instead. It reaches the same inbox.

The stores that get hurt here are not the ones with the wrong settings. They are the ones who assumed a number at checkout was a promise rather than an estimate.

Verified on 20 September 2026 against Shopify's Help Centre documentation for duties and import taxes, HS codes and Managed Markets, Shopify's July 2026 changelog, US customs rules published 24 June 2026, and Canada's Department of Finance counter-tariff announcement.