How to Calculate Your True Landed Cost (and Real Profit) on Amazon

Most sellers think they know their cost. They look at the supplier invoice, see $4.10 a unit, and build their whole pricing model on that number. Then payouts come in lower than the spreadsheet promised, and they can't explain why. The gap is almost always landed cost — the real, fully-loaded cost of getting one sellable unit into an Amazon fulfillment center, ready to ship. If you're not costing at that level, you're flying blind.

What actually goes into landed cost

Landed cost is the sum of every dollar you spend to move a unit from the factory floor to a customer-ready state. The invoice price is just the first line. Miss any of the others and your margin math is fiction.

• Invoice / unit cost — what the supplier charges per piece, after any volume breaks or sample credits.
• Freight — ocean, air, or ground, plus the drayage and trucking on both ends. Allocate it per unit, not per shipment.
• Duty and tariffs — import duty by HTS code, plus any Section 301 or anti-dumping tariffs that apply to your product and country of origin.
• Prep and packaging — poly bags, bubble wrap, labeling, bundling, inspection, and any prep-center per-unit fee.
• Inbound shipping to Amazon — the cost to send prepped units into the FBA network, including Amazon's inbound placement charges where they apply.

Add those up and divide by the number of units that arrive in sellable condition. That last part matters more than people expect.

Cost per sellable unit, not per ordered unit

You ordered 1,000 units. Forty arrive damaged, and the supplier eats none of it. Your real denominator is 960, not 1,000. Spreading the same total spend across fewer good units quietly raises your per-unit cost — and if you ignore it, every profit number downstream is inflated.

The mental model is simple: total money out, divided by total good units in. Defects, samples consumed in inspection, and units lost in transit all shrink the denominator. Build that into the habit and your landed cost stops being optimistic.

Why gross margin lies

Here's the trap that catches experienced sellers. You take your sale price, subtract landed cost, and call the difference your margin. On a $24.99 item with a $6.50 landed cost, that looks like a fat 74% — a no-brainer. But Amazon hasn't taken its cut yet.

Subtract the referral fee (commonly around 15%, though it ranges roughly 8–17% by category), the FBA fulfillment fee, monthly storage, and your share of returns, and that 74% can collapse toward single digits. Gross margin tells you almost nothing about whether a product is worth selling. Net profit per unit, after every fee, is the only number that pays you. If you want the full breakdown of what Amazon charges, see Amazon seller fees explained.

A worked mental model

Walk a unit through end to end so the layers are concrete. Numbers here are illustrative — yours will differ — but the sequence is what you should internalize.

1. Start with the invoice unit cost.
2. Add the per-unit slice of freight, duty, and any tariff.
3. Add prep, packaging, and inbound-to-Amazon shipping. That total is your landed cost.
4. Divide by sellable-unit yield to account for defects and shrinkage.
5. From the sale price, subtract landed cost, the referral fee, and the FBA fulfillment fee.
6. Subtract a per-unit reserve for returns, storage, and any advertising you run.
7. What remains is your real net profit per unit — the number to base sourcing and pricing decisions on.

Do this once by hand and you'll never trust a gross-margin shortcut again. The discipline is keeping every layer in view at once, on every SKU, every time you reprice or reorder.

Frequently asked questions

Should I include shipping to Amazon in my COGS or treat it as an expense?

Include inbound shipping to Amazon in landed cost. It's a direct cost of getting that specific unit sellable, so it belongs in your per-unit number — not lumped into general overhead where it gets ignored at the SKU level.

How do I handle freight when one shipment has several products?

Allocate the freight bill across products by a sensible driver — usually volume (cubic measure) or weight, whichever dominates the cost. Splitting it evenly per unit overcharges small items and undercharges bulky ones, which distorts which SKUs look profitable.

Do tariffs really change the math that much?

They can. An added tariff on top of base duty stacks directly onto every unit's landed cost, and on thin-margin items it's often the difference between a winner and a loser. Always cost with the tariff rate that actually applies to your HTS code and country of origin, not the base duty alone.