FBA Is Worth It. For the Right Products. With the Right Margins.
If you want a simple yes or no — it is not that simple. FBA is worth it for products with strong gross margins, manageable return rates, and standard dimensions. FBA is a margin destroyer for products with thin margins, high return rates, or outsized dimensions. The difference between those two outcomes is arithmetic, not Amazon.
What we see most often is not brands making a deliberate bad decision about FBA. It is brands making no deliberate decision at all. They assume FBA is the default, launch on it, and discover six months later that their growing revenue is not translating into growing profit. The culprit is always the same: a cost stack that was never fully calculated.
Here is the math. Not the simplified version. The real version.
The Full FBA Cost Stack on a Real Product
We will use a product we see all the time: a $35 supplement. Standard-size bottle, health and beauty category. This is representative of hundreds of accounts we have audited.
Start with $35.00 in revenue.
- Referral fee (15% for health and beauty): $5.25
- FBA fulfillment fee (standard-size, approximately 12 oz packed): $4.50
- Monthly storage fee (annualized per unit, assuming 60-day turns): $0.30
- Inbound placement fee (single-location shipment): $0.30
- Returns allowance (5% return rate, half become unsellable): $1.75
Total Amazon cost: $12.10. That is 34.6% of revenue before you spend a dollar on advertising or factor in your cost of goods.
Now add COGS. For a supplement at a reasonable manufacturing cost: $8.00.
Now add PPC. If you are running advertising at a 10% TACoS — which is on the low end for a competitive supplement category: $3.50.
Revenue $35.00 minus Amazon fees $12.10 minus COGS $8.00 minus PPC $3.50 = $11.40 contribution margin. That is 32.6%.
Is 32.6% contribution margin good? It depends on your overhead. If you have minimal fixed costs and high volume, it can work. But now run the same product with a TACoS of 15% — which is common in the launch phase — and contribution margin drops to $9.65, or 27.6%. Add a Q4 storage spike and that number compresses further.
The margins are real. They are also thin. A supplement brand that does not manage these variables tightly is always one bad quarter away from a profitability crisis.
The Gross Margin Threshold That Changes Everything
Here is the number we use internally at OBG: you need 55–65%+ gross margin before Amazon fees to run FBA profitably alongside a meaningful advertising investment.
Gross margin, in this context, means revenue minus COGS. If your $35 product costs $8 to make, your gross margin is ($35 - $8) / $35 = 77%. That is above the threshold, which means FBA's full cost stack can be absorbed and you still have room for PPC investment.
Now take a product with lower-quality COGS — say that same $35 product costs $14 to make. Gross margin is ($35 - $14) / $35 = 60%. Still above the threshold, but much less room for error.
Take the COGS to $18 and gross margin drops to 48.6%. You are below the threshold. Amazon's cost stack, at that margin level, does not leave enough room for competitive PPC investment without going negative on contribution margin. You can still sell the product on Amazon — but you will need to either charge more, spend less on ads, or find a different fulfillment model.
Below 40% gross margin, FBA with any meaningful advertising investment is almost always a money-losing proposition. We have seen brands in this situation celebrate growing revenue while their bank account quietly drains. That is not growth. That is subsidizing Amazon's ecosystem with your own capital.
The Categories Where FBA Is Most Likely Worth It
FBA's value proposition is strongest in categories with these characteristics:
- High gross margins. Supplements, skincare, consumables, specialty foods — any category where product costs are 20–35% of revenue and the item is small and light.
- Low return rates. Categories where customers rarely return products. Consumables, commodity items, products with clear specifications. In these categories, the returns line item in your cost stack stays small.
- Standard dimensions. Products that fit in Amazon's small or medium standard-size tiers pay the lowest fulfillment fees. This is where FBA's per-unit cost is most competitive with alternatives.
- Repeat purchase behavior. Subscription-eligible products benefit from FBA because Prime customers convert at higher rates on Subscribe and Save, which lowers effective TACoS over time.
The Categories Where FBA Is Most Likely a Problem
- Heavy or oversized products. Fulfillment fees for large standard or oversized items can run $10–35+ per unit. For a $60 product, a $20 fulfillment fee plus 15% referral fee plus storage is 48% of revenue before COGS or PPC. The math rarely works.
- Apparel and shoes. Return rates of 20–30% are common. The returns line item in the cost stack becomes enormous, and unsellable returned units represent direct capital destruction.
- Low-priced, high-volume commodities. A $9.99 product with a $3.50 FBA fee has 35% of its revenue consumed by that single fee before anything else is calculated. The math requires extraordinary COGS efficiency to recover.
- Products with significant seasonal demand. Q4 storage fees are three times the off-season rate. If you stock heavily for the holidays and sell through slower than projected, the storage fees on remaining inventory can erase the holiday profit.
How Breakeven ACoS Changes the Conversation
One of the most important calculations in FBA is your breakeven ACoS — the maximum ACoS at which your PPC campaigns still break even after all costs are covered. We calculate this for every product we manage using Sellerise, and it drives every PPC decision we make.
The formula: breakeven ACoS = contribution margin before PPC, divided by revenue.
Using our supplement example: $14.90 (revenue minus Amazon fees minus COGS) / $35.00 = 42.6% breakeven ACoS. This means your PPC campaigns can run up to a 42.6% ACoS before you are selling at a loss. That is actually a healthy breakeven ACoS — it gives you room to invest aggressively in PPC during the launch phase.
Now change the COGS to $14 on the same product: ($35 - $12.10 - $14) / $35 = 25.4% breakeven ACoS. Your ceiling just dropped significantly. Every campaign that runs above 25.4% ACoS is costing you money. That is a much tighter operating window.
Brands that do not calculate breakeven ACoS before launching PPC are essentially flying blind. They see ACoS of 30% and think it sounds reasonable. Whether it is reasonable depends entirely on their margin — not on the percentage itself.
Revenue is vanity. Contribution margin is sanity.
FBA in 2025: New Fees, New Considerations
Amazon added inbound placement fees in 2024, which increased the effective cost of FBA for most sellers by $0.15 to $0.50 per unit depending on shipment size and destination. This was a meaningful change that compressed margins further — particularly for small brands sending smaller inbound shipments that Amazon splits across multiple fulfillment centers.
The low-inventory fee, also introduced in 2024, charges sellers who maintain inventory levels below what Amazon considers optimal for their sales velocity. This creates a new tension: hold more inventory (higher storage cost risk) or hold less inventory (low-inventory fee). Managing this balance requires more active inventory monitoring than most sellers were doing previously.
The net effect of Amazon's 2024 fee changes: FBA became less forgiving of marginal products. Brands that were barely profitable on FBA before the changes often moved into loss territory. Brands with strong margins absorbed the additional fees without major impact. This is another reason why the 55–65% gross margin threshold matters more now than it did three years ago.
The Verdict
FBA is worth it in 2025 if you do the math before you launch, your gross margins are above 55%, your product dimensions are standard or small, and your return rate is manageable. Those conditions describe a large number of successful Amazon products. They also exclude a meaningful portion of the catalog that sellers are currently running on FBA at a loss.
Run the numbers. Use Sellerise or a comparable tool that builds in the full cost stack — not just referral fees and FBA fees. Calculate your breakeven ACoS before you set PPC targets. Know your contribution margin at each phase of your PPC lifecycle.
If the math works, FBA is excellent infrastructure. If it does not, the Prime badge is not worth what you are paying for it.
Work With OBG
Before we touch a single campaign, we calculate the full FBA cost stack and breakeven ACoS for every product in your catalog. We use Sellerise to make sure the math is honest — not optimistic. Then we build a PPC strategy that operates within the real margins, not the assumed ones.
Every new engagement comes with a 30-day profitability guarantee. If we do not improve your contribution margin in the first 30 days, you do not pay. Book a free strategy call at onlinebrandgrowth.com and let us show you what your real numbers look like.