Moving from FBA to a 3PL is usually framed as a cost decision, and cost is part of it. The bigger risk is on the revenue side. If a product converts because of the Prime badge, moving it out of FBA can save you two dollars a unit and cost you a third of your sales. So before you compare fee sheets, work through these six questions in order. Each one narrows down what, if anything, should move.
Switch from FBA to a 3PL when your all-in FBA cost per unit is clearly higher than a 3PL plus shipping, your sales don't depend heavily on the Prime badge, and you have meaningful sales outside Amazon to serve from the same inventory. If only some of that is true, a hybrid is usually better: keep fast, Prime-sensitive SKUs in FBA and move slow movers, bulky items and off-Amazon orders to a 3PL.
What Does FBA Cost You Per Unit, All In?
Most sellers know their FBA fulfillment fee by heart. Far fewer know their total FBA cost per unit sold, because the rest is spread across different reports and billing periods. To get the full figure, add up everything Amazon charged you for fulfillment and storage over the last three to six months, and divide by units sold in the same period. Include:
- Fulfillment fees
- Monthly storage, including the higher rates from October to December
- Inbound placement fees, or the cost of sending to more locations to avoid them
- Low-inventory-level fees, if you've been running lean
- Aged inventory and storage utilization surcharges
- Prep and labeling, now that you have to do it yourself or pay someone
- Removal and disposal fees
- Freight into Amazon
A hypothetical shows why it matters. A seller's fulfillment fee on a mid-sized product is $4.60, which looks fine. But over six months, storage added $0.55 per unit sold, placement fees $0.30, aged inventory surcharges (mostly from the slower half of the catalog) $0.40, prep $0.35, and inbound freight $0.45. The all-in number is about $6.65 per unit, 45% higher than the fee they'd been quoting to themselves.
Compare that figure, not the fulfillment fee, against a 3PL's pick and pack plus shipping for the same product.
How Much Is the Prime Badge Doing for You?
This is the question that decides most switches. FBA listings get Prime delivery automatically, which tends to help conversion and the Buy Box. When you fulfill your own Amazon orders (FBM), you lose the badge on standard listings and compete for the Buy Box on price, delivery promise and your seller performance.
How much that matters varies enormously by product. A few ways to estimate your own exposure:
- Look at who wins the Buy Box on similar listings. If Prime offers win nearly every time in your category, expect a real drop without it.
- Consider how customers find you. Branded searches (people looking for you by name) are less sensitive to Prime than generic ones like "stainless water bottle."
- Test it. Move one or two representative SKUs to FBM for a few weeks, with realistic delivery promises, and compare conversion and Buy Box percentage in your business reports.
If losing Prime would cost you significant sales, Seller Fulfilled Prime is the route that lets a 3PL ship while keeping the badge, though its performance requirements are demanding.
How Much Do You Sell Outside Amazon?
A 3PL's biggest advantage over FBA is that one inventory pool can serve every channel. If 90% of your revenue is Amazon, that advantage is small. If you're doing real volume on your own site, Walmart, TikTok Shop or wholesale, it's large.
Also look at how you fulfill those other channels today. If you're using Amazon's Multi-Channel Fulfillment for Shopify orders, you're paying Amazon's rates plus a premium, and you're limited in packaging and inserts. If you're shipping them from a garage while your main stock sits at Amazon, you're running two inventories. Either way, a 3PL consolidates it.
Can a 3PL Match the Delivery Speed Your Customers Expect?
Amazon has spent billions building a network that puts inventory close to customers. A single 3PL warehouse can't match that on every order, and it doesn't need to. What it needs to do is ship the same day for orders received before the cutoff, and reach most of your customers in a reasonable ground window.
Ask any 3PL you're considering for its daily cutoff time, its on-time shipping record, and a ground transit map from its building. A warehouse in the middle of the country keeps the average transit time down. If most of your customers are on one coast, look for a warehouse closer to them.
What Will the Move Itself Cost?
Switching isn't free, and the costs land before the savings do.
Removal order fees per unit, plus freight from Amazon's buildings. Removals can take weeks to process, especially late in the year.
Removals often arrive as mixed cartons with Amazon labels on every unit. Expect extra receiving labor to sort and relabel.
Plan inventory so listings never go out of stock between channels. Send new production to the 3PL rather than removing everything from FBA.
Integration, SKU setup and a few weeks of adjustment. Budget time as well as money.
The cheapest way to move is often not to remove anything. Let FBA sell down its current stock and send your next production run to the 3PL instead.
Would a Split Beat a Full Switch?
After working through the first five questions, most sellers find their catalog divides into two groups. Some SKUs sell fast, depend on Prime and cost little to store. They belong in FBA. Others sell slowly, are bulky, attract surcharges, or sell mostly off Amazon. They cost less to hold and ship from a 3PL.
The hybrid gives you both. The 3PL holds your main inventory, ships your own site and other marketplaces, and sends smaller, more frequent replenishment to FBA for the fast movers. FBA stays lean, which keeps storage fees and aged surcharges down, and your capacity limits stop dictating how much stock you can hold.
For a wider look at the options, see 6 FBA Alternatives for Sellers Tired of Rising Amazon Fees.
Frequently Asked Questions
For some products, yes. Slow movers, oversized items and products hit by storage surcharges often cost less to fulfill from a 3PL. Fast-moving, small items can be cheaper in FBA. Compare your all-in FBA cost per unit, including storage, placement fees, surcharges, prep and freight, against a 3PL's fees plus shipping.
It can. FBM listings lose the Prime badge and compete on price, delivery promise and seller performance. The impact depends on your category and how customers find you. Test with a few SKUs before moving more.
Yes, and many sellers do. A common setup keeps fast-selling SKUs in FBA while a 3PL holds backstock, fulfills other channels and replenishes FBA in smaller shipments.
You can create removal orders to send inventory to your 3PL, but that incurs fees and can take weeks. Often it's simpler to let FBA sell through its current stock and send new production to the 3PL instead.
A single warehouse can't match Amazon's network on every order, but a 3PL that ships same day and sits centrally can reach most US customers within a few days by ground. Ask for its cutoff time and a transit map.
The weeks leading into Q4. Removals slow down, carriers and warehouses are at capacity, and any sales disruption hurts most. Plan a move for the first half of the year if you can.
Want help running these numbers?
Send us your FBA fee reports and your sales by channel. We'll show you which SKUs would cost less to ship from our warehouse, and which ones we'd tell you to leave at Amazon.