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Amazon FBA vs. Merchant Fulfilled: Which Is Right for Your Business?

Compare the pros and cons of Amazon FBA versus merchant fulfillment. Learn when to use each option, how to calculate true costs, and strategies for maximizing profit on each path.

Jessica Torres · Marketplace Specialist
November 12, 2025
8 min read

The Amazon Fulfillment Decision

One of the most important decisions Amazon sellers face is how to fulfill orders. Should you ship products yourself (Merchant Fulfilled) or let Amazon handle it (FBA)? The answer depends on your business model, product types, and growth goals.

Understanding FBA (Fulfillment by Amazon)

With FBA, you send inventory to Amazon’s warehouses. When customers order, Amazon picks, packs, and ships the products.

FBA Advantages

Prime Badge Benefits

  • Access to Prime customers (over 200 million members)
  • Higher visibility in search results
  • Increased buy box win rate
  • Customer trust in fast, reliable shipping

Operational Simplicity

  • No packing or shipping required from you
  • Amazon handles customer service for fulfillment issues
  • Returns processing handled automatically
  • Scale without increasing your labor

Multi-Channel Fulfillment

  • Use FBA inventory to fulfill orders from other channels
  • Consistent shipping experience across platforms

FBA Disadvantages

Cost Structure

  • Fulfillment fees per item
  • Monthly storage fees
  • Long-term storage fees for slow-moving inventory
  • Prep and labeling requirements

Loss of Control

  • Cannot inspect products before shipping
  • Commingled inventory risks
  • Limited branding opportunities in packaging

Understanding Merchant Fulfilled

With Merchant Fulfilled (FBM), you store inventory and ship directly to customers.

FBM Advantages

Cost Control

  • No FBA fees
  • No storage fees
  • Potential savings on high-volume or heavy items

Inventory Control

  • Inspect each item before shipping
  • Custom packaging and branding
  • No commingling concerns

Flexibility

  • Ship same-day for local customers
  • Handle unique or fragile items personally
  • Maintain inventory at your location

FBM Disadvantages

Competitive Disadvantages

  • No Prime badge (unless Seller Fulfilled Prime qualified)
  • Lower buy box win rate against FBA sellers
  • Customer perception of slower shipping

Operational Burden

  • Daily shipping requirements
  • Customer service for shipping issues
  • Storage space requirements

Cost Comparison Framework

FBA Cost Calculation

For each product, calculate:

  • Fulfillment fee (based on size and weight)
  • Monthly storage fee (cubic feet x rate)
  • Estimated long-term storage fees
  • Prep/labeling costs if needed

FBM Cost Calculation

Calculate:

  • Shipping supplies (boxes, tape, labels)
  • Carrier costs (USPS, UPS, FedEx)
  • Your time (hourly rate x time per order)
  • Storage space (rent/sq ft x space used)

The Break-Even Analysis

Compare total costs at different volume levels. Often:

  • Low volume: FBM can be cheaper
  • High volume: FBA economies of scale kick in
  • Heavy/large items: FBM often wins
  • Small/light items: FBA often wins

Category-Specific Recommendations

Best for FBA

  • Small, lightweight items
  • Fast-selling products
  • Commodity goods with Prime-dependent sales
  • Products where Prime badge significantly impacts conversion

Best for FBM

  • Heavy or oversized items
  • Slow-moving inventory
  • High-value items requiring inspection
  • Items with low margins where FBA fees eliminate profit
  • Vintage or one-of-a-kind items

Hybrid Approach

Many successful sellers use both:

  • FBA for high-velocity Prime-eligible items
  • FBM for heavy, oversized, or slow-moving products
  • Test new products FBM before committing to FBA

Making the Transition

Moving to FBA

  1. Select your best-selling, Prime-suitable products
  2. Calculate FBA profitability for each
  3. Create FBA shipment for profitable items
  4. Monitor performance and expand

Optimizing FBM

  1. Invest in shipping efficiency (thermal printers, supplies)
  2. Negotiate carrier rates based on volume
  3. Consider Seller Fulfilled Prime qualification
  4. Streamline your packing process

ListForge Integration

ListForge helps you make the FBA vs. FBM decision:

  • Estimated profitability calculations for both options
  • Size and weight-based fulfillment cost estimates
  • Sell-through rate predictions
  • Recommendations based on product characteristics

The Bottom Line

There’s no universal right answer. The best fulfillment strategy depends on:

  • Your product mix
  • Your operational capacity
  • Your margin requirements
  • Your growth goals

Start with data. Test both approaches. Let results guide your strategy.