COGSCost of Goods Sold
COGS is the direct cost of producing or purchasing the products you sell. It is the foundation of every profitability calculation in ecommerce.
What is COGS?
Cost of Goods Sold includes every direct cost tied to bringing a product to a sellable state: the unit manufacturing or purchase cost, inbound shipping from supplier to warehouse, import duties and customs fees, and direct packaging materials. It does not include operating expenses such as advertising, software subscriptions, warehouse rent, or salaries — those are operating costs tracked separately.
Gross Profit = Revenue − COGS. Gross Margin % = (Revenue − COGS) ÷ Revenue × 100. These two calculations are the most fundamental financial metrics for any product business. If your COGS is too high relative to your selling price, no amount of marketing, PPC optimisation, or listing improvement can make the business profitable. COGS is the floor beneath which everything else stands.
For Amazon sellers specifically, true landed COGS must also account for FBA fulfillment fees and referral fees, because these are unavoidable costs of making a sale. Some sellers track 'Amazon-adjusted COGS' that bakes in these fees to get a clearer picture of per-unit profitability before advertising.
Why it matters for sellers
COGS determines your break-even price, your ACoS ceiling, your gross margin, and ultimately whether the business is viable. A seller with 20% gross margin has almost no room for advertising, returns, or promotions before going negative. A seller with 65% gross margin can afford aggressive PPC, heavy promotions, and still build a profitable business.
Reduction in COGS is pure profit. If you negotiate your manufacturer down by $1.50 per unit and sell 2,000 units per month, that's $3,000/month in additional profit requiring zero extra revenue. This is why sourcing and supply chain negotiation is one of the highest-leverage activities for any ecommerce seller.
How to use COGS
Build a unit economics spreadsheet before launching any product. Map out: unit cost, freight (divide total shipping cost by units shipped), import duty %, packaging, FBA fee (use Amazon's FBA Calculator), referral fee (typically 8–15% of sale price depending on category), and any storage fees. Subtract all of these from your planned selling price to see true per-unit profit.
Review COGS quarterly. As order volume grows, negotiate volume pricing with suppliers (tiered pricing at 500, 1,000, 2,000 units). Consider sea freight over air once volumes justify it — the cost difference is typically 60–80% cheaper per unit and can transform margins on high-volume SKUs.
Real-world example
You sell a supplement at $35. COGS breakdown: capsules + bottle $6.50, label + packaging $0.80, sea freight + duty $1.20, FBA fee $4.80, Amazon referral fee (15%) $5.25. Total cost: $18.55. Gross profit per unit: $16.45. Gross margin: 47%. You can afford a target ACoS of up to 47% before advertising erases gross profit — in practice you target 25% ACoS for a healthy net margin.
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Frequently asked questions about COGS
What is included in COGS for an ecommerce seller?
COGS includes the product purchase or manufacturing cost, inbound freight from supplier, import duties, and direct packaging. For Amazon sellers, many also include FBA fees and referral fees in their 'fully-loaded COGS' to see true per-unit economics before advertising.
What is the difference between COGS and operating expenses?
COGS is directly tied to producing or acquiring each unit sold. Operating expenses (opex) are the costs of running the business — advertising, software, salaries, rent. Gross profit = Revenue − COGS. Net profit = Gross profit − Opex. Both matter; the distinction clarifies which costs scale with sales volume (COGS) and which are more fixed (opex).
How can I reduce my COGS?
The main levers: negotiate unit price with suppliers (volume commitments help), switch from air to sea freight, reduce packaging costs by simplifying design or switching materials, consolidate shipments to improve freight efficiency, and audit import classification codes to ensure you're paying the correct duty rate — not more.
Why does COGS matter for Amazon PPC?
Your COGS determines your gross margin, which sets the ceiling for your target ACoS. If COGS is high and margins are thin, even a modest ACoS can wipe out profitability. Knowing your true COGS-based margin is the only way to set PPC budgets and bid targets that keep the business solvent.