Amazon vs. DTC: How to Calculate What Each Channel Actually Costs You

Most brands that sell on both Amazon and their own store know exactly which channel brings in more revenue. Almost none of them can tell you which channel makes more profit — and those are very different questions.

Revenue is easy to see; it's right there in each dashboard. True margin is hidden, because the costs that eat it live in five different places and none of them line up between the two channels. So brands default to the number they can see, keep pouring budget into the bigger top-line channel, and quietly leave margin on the table. Here's how to actually compare the two.

First, though, let's be clear about something: this isn't an anti-Amazon article.

Amazon is a phenomenal channel — that's exactly why it needs scrutiny

Amazon isn't a cost center you tolerate; for most brands it's the single fastest way to reach buyers who are ready to purchase right now. It's worth being honest about what it gives you:

• Demand you don't have to create. Over 200 million Prime members are already searching with their wallets open. On Amazon you're capturing existing demand; on DTC you usually have to generate it from scratch.
• Instant trust and conversion. The Prime badge, fast shipping, and Amazon's returns guarantee do a huge amount of conversion work for you. A new brand converts far better on Amazon than on a storefront no one has heard of yet.
• Logistics at a scale you couldn't build alone. FBA handles pick, pack, ship, customer service, and returns across the country — and often cheaper than a small brand could negotiate on its own.
• A discovery engine. Ranking for a high-volume keyword can put you in front of thousands of new customers a week with no email list required.

Those are real, compounding advantages. The point of this post isn't that Amazon is expensive and DTC is better — it's that each channel earns its keep in a different way, and you can only see how well when you measure the true economics of both. So let's measure.

Why revenue is the wrong scoreboard

Imagine a SKU that does $100,000 a year on Amazon and $40,000 on your DTC store. Amazon looks like the obvious winner — it's 2.5x bigger.

Now layer in the costs. On Amazon you're paying a referral fee, FBA fulfillment and storage, returns processing, and ad spend just to stay visible on your own listing. On DTC you're paying payment processing, shipping, and customer acquisition — but no referral fee, no FBA, and you keep control of the margin. It's entirely possible that the $40,000 DTC channel takes home more actual profit than the $100,000 Amazon channel.

Same brand, same product. The bigger channel is the less profitable one. If you're optimizing for revenue, you're optimizing for the wrong number.

The five costs that hide your true margin

To compare channels honestly, you have to strip each one down to net contribution. These are the buckets that matter.

1. Platform / referral fees

Amazon takes a referral fee on almost every category (commonly around 15%). Your DTC store has no equivalent — but it does have a platform subscription and app costs you should amortize per order.

2. Fulfillment

On Amazon this is FBA: pick-and-pack, weight-based fees, and monthly storage that spikes in Q4. On DTC it's your 3PL or in-house fulfillment plus outbound shipping. These rarely cost the same per unit, and the gap widens for bulky or heavy products.

3. Payment processing

Effectively invisible on Amazon (it's baked into the referral fee), but very real on DTC — typically ~2.9% + a fixed fee per transaction. Easy to forget, and it comes straight out of margin.

4. Returns and refunds

Both channels have them, but Amazon's returns are often more frequent and less in your control, and you may eat fulfillment costs on the way out and back. On DTC you set the policy.

5. Advertising and customer acquisition

This is the big one. On Amazon, ad spend does double duty: it defends your existing listings and puts you in front of high-intent shoppers who are already ready to buy — which is why Amazon ROAS is often strong. On DTC, acquisition cost is usually higher up front because you're creating demand rather than capturing it — but it buys you something Amazon doesn't (more on that in a moment). Neither is "better"; they're just different kinds of spend, and you want to know the real cost of each.

A simple framework to compare them

You don't need a finance degree. You need the same math applied to both channels, per unit.

1. Start with net selling price. The actual price the customer pays, minus any promotions or coupons.
2. Subtract COGS. Your landed product cost — identical across both channels, which makes it your anchor.
3. Subtract channel-specific fees. Referral + FBA on Amazon; payment processing + platform costs on DTC.
4. Subtract fulfillment and shipping. Whatever it actually costs to get one unit to one customer on that channel.
5. Subtract allocated ad spend. Total channel ad spend divided by units sold on that channel — your real, blended acquisition cost.

What's left is net contribution per unit. Do it for both channels and put them side by side. Now — and only now — do you know which channel deserves your next dollar.

Both channels compound — just in different ways

Here's the nuance most spreadsheets miss. Many of Amazon's costs are recurring — you pay the referral fee and the FBA fee on every order. But Amazon compounds in its own way too: the organic rank and review base you build make each future sale easier and cheaper to win, which is a real, durable asset you shouldn't discount.

DTC's biggest cost — customer acquisition — is mostly up front. You pay to acquire the customer once. If they come back, that second, third, and fourth order carries dramatically lower cost because you already own the relationship and the channel to reach them.

So both channels compound — just differently. Amazon compounds your visibility; DTC compounds your customer relationships. A simple per-unit snapshot can understate both, because it treats one-time investments as if you'll pay them on every order. That's the bridge to the bigger question — customer lifetime value — which we'll tackle in the next post.

Where this gets hard (and where a tool helps)

You can absolutely build this in a spreadsheet, and for a single SKU you should — it's the fastest way to understand the shape of your economics.

It gets painful at scale. FBA fees change. Storage spikes seasonally. Ad spend moves weekly. Do it across dozens of SKUs and two channels and the spreadsheet becomes a part-time job that's out of date the moment you finish it. That's the exact problem we built the profitability calculator in Meridian Flows to solve: it pulls your real numbers from both channels, applies the same net-contribution math per SKU, and lets you adjust the assumptions live so you can see — instantly — which products are quietly more profitable on DTC than on Amazon.

The goal isn't to abandon Amazon. It's to stop guessing, so every product lives on the channel where it actually makes you the most money.

Want to see your own Amazon-vs-DTC margin side by side? Start a free trial and run your top SKU through the profitability calculator.