International expansion gets pitched to successful US sellers constantly, often framed as the obvious next step once domestic sales plateau — new marketplace, same product, presumably similar results. The actual numbers agree with that pitch a lot less often than the pitch implies, and we've talked more than one client out of an expansion that would have quietly lost money for a year before anyone admitted it wasn't working.
The cost structure isn't the same market with different currency
Referral fees are broadly similar across Amazon Canada, the UK, and the EU marketplaces, but everything else in the cost stack shifts. FBA fulfillment fees differ by marketplace. VAT registration and ongoing compliance in the UK and EU is a real, recurring cost and administrative burden that doesn't exist for a US-only seller — and unlike US sales tax, which Amazon largely handles through Marketplace Facilitator rules, VAT obligations in several EU scenarios still fall on the seller directly. Currency conversion fees on payouts, if you're not settling in local currency, quietly erode margin on every single sale in a way that's easy to miss until you add it up over a quarter.
Inventory splits your working capital, not just your stock
This is the part sellers underestimate most. Expanding into a new marketplace means holding inventory in that marketplace's fulfillment network, which means capital that used to support one inventory pool now has to stretch across two or three, each with its own reorder timeline and its own risk of stockout or excess storage fees. For a seller already managing tight Q4 planning in the US alone, adding a second or third inventory pool without additional working capital to support it is one of the more common ways international expansion turns into a cash flow problem rather than a growth story.
Demand doesn't transfer as directly as sellers assume
A product that's a strong seller in the US isn't automatically a strong seller in Canada, the UK, or Germany. Category competitiveness, price sensitivity, and even product-market fit can differ meaningfully — a product solving a very US-specific problem, sized to US standards, or priced against US competitive norms can land completely differently in a market with different baseline expectations. We run keyword and competitive research specific to each target marketplace before recommending expansion, the same way we would for a new product launch, rather than assuming US keyword research or US demand data transfers directly.
The math that actually decides it
Before recommending expansion to a client, we build out landed cost per unit including the destination marketplace's FBA fees, estimated advertising cost to establish rank in a market where you have no existing review base or sales history, and a realistic timeline for VAT registration and compliance setup if the UK or EU is involved — that alone can take four to eight weeks before you can legally sell. If the resulting margin, after all of that, doesn't meaningfully beat what the same capital and attention would generate by reinvesting in the US business — a new ASIN, deeper PPC investment, or an underserved variant of an existing product — expansion usually isn't the right move yet, regardless of how appealing "sell in five countries instead of one" sounds.
When it does make sense
Sellers with strong margins, stable US demand, and products without heavy localization requirements (no significant sizing, language, or regulatory differences between markets) tend to see the best results from expansion, particularly into Canada first, which shares more operational and cultural similarity with the US than the UK or EU markets do. It's a reasonable second market to test the internationalization process on before committing further.
If you're considering expansion and want an honest read on whether the numbers actually support it for your specific product, that's exactly the analysis we run before recommending anything. Book a free consultation and bring your current US margins — we'll model it out together.