FBA vs FBM: Which Fulfilment Method Gives Importers Better Margins?

FBA vs FBM: Which Fulfilment Method Gives Better Margins?

FBA vs FBM — which fulfilment method gives importers better margins? Whether you're selling on Amazon US, UK, or EU, choosing between Fulfilment by Amazon (FBA) and Fulfilment by Merchant (FBM) is one of the most consequential decisions you will make. It affects your cost structure, your Buy Box eligibility, your customer service workload, and ultimately your profit margins.

Most guides present FBA as the obvious choice. For many products it is — but not for all. As an importer, your cost base is already complex with landed cost components like freight, duty, and VAT. Adding the wrong fulfilment costs on top can turn a viable product into a loss-maker.

This guide compares FBA and FBM from an importer's perspective, with worked examples for three different product types.

How FBA Works

With FBA, you ship your inventory to Amazon's fulfilment centres. When a customer places an order, Amazon picks, packs, and ships the product. Amazon also handles customer service and returns for FBA orders.

You pay:

• Fulfilment fees — per-unit fees based on size and weight
• Monthly storage fees — per cubic foot, higher in Q4 (October–December)
• Long-term storage fees — for inventory stored over 365 days
• Removal/disposal fees — if you need to pull unsold stock out
• Referral fees — percentage of selling price (same for FBA and FBM)

How FBM Works

With FBM, you store inventory in your own warehouse (or a third-party logistics provider) and ship directly to customers when orders come in. You handle customer service and returns.

You pay:

• Warehouse rent or 3PL storage fees
• Pick, pack, and ship costs (your labour or 3PL fees)
• Shipping costs (USPS, UPS, FedEx, Royal Mail, DPD, etc.)
• Packaging materials
• Returns handling
• Referral fees — same percentage as FBA

Cost Comparison: The Numbers

Let's compare costs for three different product types that importers commonly sell.

Product A: Small, Lightweight Item (Phone Case)

Winner: FBA — Amazon's scale gives them lower fulfilment costs than most small sellers can achieve for lightweight items. The margin difference of 9.3 percentage points is significant over thousands of units.

Product B: Medium Item (Stainless Steel Water Bottle)

Roughly even — At this size and price point, the costs are very similar. FBA's slight advantage comes with the added benefit of Prime eligibility and Buy Box weighting. For most importers, FBA wins here on convenience.

Product C: Large, Heavy Item (Garden Furniture Set — 15kg)

Winner: FBM — For large, heavy items, Amazon's size-based fulfilment fees become expensive. A 3PL or your own warehouse can often beat Amazon's pricing, especially if you negotiate good courier rates for bulky items.

The Buy Box Factor

Cost alone does not tell the full story. The Buy Box — the prominent "Add to Basket" button — drives roughly 80% of Amazon sales.

FBA sellers receive a significant advantage in Buy Box eligibility. Amazon trusts its own fulfilment network to deliver on time, so FBA offers are weighted more favourably.

For FBM sellers to compete for the Buy Box, you need:

• Excellent seller metrics (order defect rate below 1%, late shipment rate below 4%)
• Competitive pricing (often lower than FBA sellers to compensate)
• Fast shipping (same-day or next-day dispatch)
• Seller Fulfilled Prime (if you qualify, this levels the playing field)

If FBM saves you $1.39 per unit but you lose 20% of your sales because of reduced Buy Box visibility, the maths does not work in your favour.

When FBA Wins for Importers

FBA is typically the better choice when:

• Your products are small to medium-sized — fulfilment fees are reasonable relative to your selling price
• You sell fast-moving products — low storage costs because inventory turns over quickly
• You value simplicity — no need to manage warehouse staff, shipping accounts, or customer service
• You want Prime eligibility — the Prime badge increases conversion rates by 25–50% for many products
• You sell across multiple European marketplaces — Amazon's Pan-European FBA or European Fulfilment Network handles cross-border logistics

For importers specifically, FBA has another advantage: you can ship directly from your supplier (or freight forwarder) to Amazon's fulfilment centres, avoiding the need for your own warehouse entirely.

When FBM Wins for Importers

FBM becomes the better choice when:

• Your products are large or heavy — Amazon's oversized fulfilment fees are punishing
• Your products are slow sellers — long-term storage fees erode margins on slow-turning inventory
• You sell high-value items — the fixed fulfilment fee is a smaller percentage of the selling price, and you want more control over packaging and presentation
• You have an existing warehouse or 3PL — the marginal cost of adding Amazon orders to your existing operation is low
• You sell fragile or customised products — better control over packing quality reduces damage rates
• You want to own the customer relationship — branded packaging, inserts, and personalised touches are easier with FBM

The Hybrid Approach

Many successful importers use both FBA and FBM:

• FBA for best sellers — high-volume products where Prime eligibility and fast shipping drive sales
• FBM for slow movers — products that sell a few units per week, where long-term storage fees would eat into margins
• FBM as a backup — when FBA inventory runs out, FBM listings keep you selling while replenishment is in transit
• FBM for oversized items — large products where your own logistics are cheaper

This hybrid strategy requires more operational complexity but can optimise margins across your entire product range.

Storage Cost Comparison: Amazon vs 3PL

Storage fees deserve special attention for importers because you are often dealing with full container loads that need to be stored somewhere.

Amazon FBA storage (2025/2026 approximate rates in USD):

• Standard-size: $0.95 per cubic foot per month (January–September)
• Standard-size: $1.90 per cubic foot per month (October–December)
• Oversize: $0.64 per cubic foot per month (January–September)
• Oversize: $1.27 per cubic foot per month (October–December)
• Aged inventory surcharge: applies after 180+ days

Storage fees differ by marketplace — Amazon US, UK, and EU each publish their own rate cards. Check your marketplace's seller central for exact figures.

Typical 3PL storage:

• Pallet storage: $10–$19 per pallet per week ($40–$76 per month)
• Shelf storage: $0.50–$1.00 per cubic foot per month
• No seasonal surcharges
• No long-term penalties (though some charge for slow-moving stock)

For fast-selling products, Amazon's storage is competitive. For seasonal or slow-moving inventory, a 3PL is almost always cheaper because you avoid the Q4 surcharge and aged inventory penalties.

Returns Handling Differences

Returns are an unavoidable part of selling on Amazon UK. How they are handled differs significantly:

FBA returns:

• Amazon processes the return automatically
• The customer gets an instant refund
• Items are assessed and either returned to sellable inventory or marked as unfulfillable
• You pay a return processing fee
• You have limited control over the process

FBM returns:

• You manage the return process
• You can inspect items yourself and decide whether to resell, refurbish, or write off
• You have more control over refund timing and restocking decisions
• You bear the labour cost of processing returns

For importers, the key consideration is whether returned items can be resold. With FBA, Amazon's assessment is binary — sellable or unfulfillable. With FBM, you might refurbish items that Amazon would have written off, recovering more value.

Impact on Profitability: A Summary View

Choose the Right Fulfilment Strategy for Your Products

For most importers starting out, FBA is the right default choice. It simplifies operations, provides Prime eligibility, and lets you focus on sourcing and marketing rather than logistics.

As your business grows and you develop relationships with 3PLs, FBM becomes a powerful tool for specific product types — particularly large, heavy, or slow-selling items.

Use the FBA Calculator to model your specific products. Input your landed cost, product dimensions, and selling price to see exactly what your FBA margins would be. Then compare that against quotes from 3PL providers to make an informed decision.

For a complete breakdown of every Amazon fee, see our Amazon FBA fee breakdown 2026. To understand how to set profitable prices once you have chosen your fulfilment method, read our guide on pricing imported products on Amazon UK.

The best fulfilment strategy is the one that maximises your profit per unit while maintaining the sales velocity you need to hit your revenue targets. For many importers, that means a hybrid approach — and that is perfectly fine.