Amazon FBA vs FBM Calculator
Compare fulfillment costs and profit margins side-by-side to choose the right fulfillment method.
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FBA Costs
FBM Costs
FBA vs FBM: Which Is Better?
There's no universal winner — the right fulfillment method depends on your product, margins, and operational capabilities. FBA gives you the Prime badge, which can significantly increase conversion rate and sales volume. FBM gives you more control, lower per-unit costs on large or heavy items, and no storage fee risk.
The key is to model both options with your actual cost data. FBA often looks more expensive on a per-unit basis, but if the Prime badge lifts conversions by 20–30%, the higher unit economics might still result in better total monthly profit. Our FBA vs FBM comparison guide walks through the full decision framework with real-world examples.
When FBM Makes More Sense
- Large, heavy, or oversized items where FBA fees would consume most of the margin
- Slow-moving products where FBA storage fees would be significant
- Custom, handmade, or made-to-order items that can't be pre-stocked in FBA
- Hazmat, restricted, or category-specific items that FBA won't accept
- Sellers with existing warehouse infrastructure who can match or beat FBA logistics costs
When FBA Makes More Sense
- Standard-size, lightweight products where FBA fees are low relative to selling price
- High-velocity products with fast turnover (minimizing storage fees)
- When you don't have warehouse space or logistics infrastructure
- When you want to focus on sourcing/marketing rather than operations
- Products in competitive categories where the Prime badge is a meaningful differentiator
Frequently Asked Questions
Can I use both FBA and FBM for the same ASIN?
Yes — this is called a "hybrid" or "split" approach. Many sellers keep their primary stock in FBA but also have an FBM offer as a backup. If you go out of stock in FBA, the FBM listing can continue selling (though without Prime). You can also use FBM for overflow during peak seasons when FBA storage fees are highest.
Does FBM affect Buy Box eligibility?
FBM sellers can win the Buy Box, but they must offer Prime-competitive shipping (ideally 2-day) and maintain excellent performance metrics. Seller Fulfilled Prime (SFP) is one route to get the Prime badge with FBM, but it has strict requirements. In practice, FBA sellers have a significant advantage for the Buy Box.
What FBA fees should I include?
The main FBA cost inputs are: (1) fulfillment fee (based on size/weight), (2) monthly storage fee (cubic feet × monthly rate), and (3) inbound shipping to FBA. Use the FBA fee calculator to estimate your fulfillment fee by product dimensions and weight.
Does the Prime badge really increase sales enough to justify FBA?
Studies consistently show Prime-eligible listings convert at significantly higher rates — often 2–3× compared to non-Prime. However, the actual lift for your specific product depends on category, competition level, and price point. The best approach is to test both and measure actual conversion rates rather than relying on averages.
Frequently Asked Questions
- When is FBM more profitable than FBA?
- FBM tends to be more profitable for heavy or bulky items where FBA fulfillment fees are high, products with slow sales velocity where FBA storage fees accumulate, items with very low selling prices where FBA fees consume a large percentage, and products where you already have efficient fulfillment infrastructure.
- Does FBM hurt my chances of winning the Buy Box?
- FBA sellers have an inherent advantage for the Buy Box due to Amazon's preference for Prime-eligible listings. FBM sellers can compete for the Buy Box by enrolling in Seller Fulfilled Prime (SFP), which requires meeting strict shipping speed and performance metrics, but grants Prime badge eligibility.
- What costs are unique to FBM that don't apply to FBA?
- FBM-specific costs include: your outbound shipping to the customer (you pay this directly instead of Amazon), packaging materials (boxes, void fill, tape), labor for picking and packing, and any warehouse or storage costs you incur. Amazon's FBM referral fee is the same as FBA.
- Can I run FBA and FBM simultaneously?
- Yes. Many sellers maintain FBA as the primary fulfillment method and list FBM as a backup during stockouts. Some run FBM for slower-moving SKUs to avoid FBA storage fees. You can list the same ASIN under both fulfillment methods in Seller Central.
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