Amazon vs Shopify Profitability: How to Compare Them Honestly

The two platforms don't hand you the same kind of number. Shopify's sales reports show revenue before payment processing comes off. Seller Central shows gross ordered sales too — but what actually lands in your bank from Amazon is the disbursement, and that is already net of the referral and FBA fees. Plenty of sellers compare the figure they feel on each side: Shopify sales against the Amazon payout. Line those two up and Amazon looks worse than it is, sometimes dramatically, purely because one number has had its fees taken out and the other hasn't.

Compare the two gross figures instead and the mistake flips: now Amazon looks better than it is, because a large share of that revenue goes straight back to Amazon in fees.

Either way, the fix is to stop comparing revenue and compare what's actually left: contribution margin, calculated the same way for both channels, with every fee added back in explicitly rather than netted out somewhere upstream.

No referral fee and no marketplace cut — that's Shopify's structural advantage. What you do pay: payment processing (commonly around 2.9% + a fixed fee unless you're on Shopify Payments at a negotiated rate), your own shipping and packaging, and every dollar of ad spend it took to bring the customer to your store yourself. Unlike Amazon, Shopify doesn't hand you the traffic — the acquisition cost lives entirely on your side of the ledger.

Amazon's referral fee (commonly around 15%, category-dependent) and FBA fulfilment fee typically take 25–40% of the sale price before anything else is subtracted — the full breakdown and a worked per-unit example are in the FBA fees guide linked below. In exchange, Amazon supplies the buyer: PPC still costs money, but the organic search traffic and Prime-eligible trust that drive a sale often cost less to generate than the equivalent Shopify visitor.

This is the real trade sellers are making, and it's rarely stated this plainly: Amazon takes a bigger cut of each sale and hands you a customer who was often cheaper to acquire. Shopify keeps more of each sale and asks you to pay for the customer yourself.

Take one product and run it through the same contribution-margin calculation twice — once with Amazon's costs, once with Shopify's. A $40 product costing $12 to make: on Amazon, a 15% referral fee ($6) plus a $6 FBA fee plus $4 of PPC leaves $12 of contribution, a 30% margin. The same product on Shopify, with a 3% payment fee ($1.20), $5 of your own shipping and $8 of ad spend to win the sale, leaves $13.80 — a 34.5% margin, and this time the ad line is the one you control.

Neither number is "correct" in isolation — they answer different questions. The Amazon margin tells you what's left after Amazon does the selling for you; the Shopify margin tells you what's left after you do it yourself. Run both through the calculator below with your own costs, changing only the marketplace fee and the ad-spend line between the two, and the honest comparison falls out.

Forgetting storage and long-term storage fees. FBA charges rent on the shelf space your inventory occupies, and it climbs sharply on stock that sits past a few months. A product with a healthy per-unit margin can still lose money in aggregate if it turns over slowly — check inventory age, not just the per-unit calculation.

Using list ACoS instead of true ad cost per unit. Amazon PPC reports ACoS per campaign, not per unit sold organically alongside it. If a campaign drives some sales directly and lifts organic rank for others, attributing all the spend to only the directly-tracked sales overstates true Amazon profitability. Blend total ad spend against total units sold in the period, not just the attributed ones.

Comparing a mature Shopify store to a new Amazon listing (or the reverse). A brand-new Amazon listing pays more in PPC to build initial velocity than the same listing will a year in, once it holds organic rank. Judge channel profitability on a listing that's had time to settle, not week one.

For most sellers, Shopify carries a higher per-unit contribution margin because it isn't paying a referral fee — but that margin arrives slower and costs more to build, because every visitor has to be individually earned or bought. Amazon's margin is thinner but the volume tends to arrive faster, because Amazon is doing part of the acquisition job for you.

Neither answer generalises to your specific products. A commodity item in a crowded Amazon category can lose to PPC costs that a differentiated Shopify brand never pays; a product with weak organic Shopify traffic can outperform easily on Amazon's built-in search volume. Run the calculation per product, and expect the winner to differ by SKU.

Being direct about status: Shopify is in early access today; the Amazon Seller API connector is built but still in Amazon's approval queue, so a live board showing both channels' contribution margin side by side isn't something you can switch on this afternoon. The calculators below work today with no signup — run your own numbers through them per channel and you'll have the honest comparison without waiting on any connector.

When Amazon connects, the plan is the tile version of this guide: the same contribution-margin math, per channel, updating on its own instead of being pasted in by hand.