A Guide to Switching From FBS to FBA

Switching an existing Amazon listing to Fulfilled by Amazon comes down to three console tasks. You enable FBA on the seller account you already have, you convert the listings you want Amazon to fulfill (Manage Inventory, then Edit, then Change to Fulfilled by Amazon), and you move your stock to a fulfillment center through the Send to Amazon workflow. The rest of this page walks through the decisions inside each of those tasks and what changes once Amazon starts fulfilling your orders.

One note on names before the steps: Amazon's own term for a listing you fulfill yourself is Fulfilled by Merchant (FBM), while many sellers say Fulfilled by Seller (FBS) for the same model, as this page's title does. The guide below sticks to Amazon's labels, because those are the words on the buttons you'll be clicking.

This guide is written for sellers with live FBM listings and stock on hand. If you're starting from nothing, our guide to building an Amazon FBA business covers that ground, and if you want the program explained before you commit to it, start with What Does Fulfilled by Amazon (FBA) Mean?

Before you switch: run the numbers

The clicks are the quick part of a fulfillment switch; the expensive mistakes happen in the decisions behind them, so work through this list before you open Manage Inventory.

• Check every product against FBA's restrictions. Amazon tells sellers to review FBA product restrictions and the program's policies and requirements before choosing what to enroll. Some ASINs won't qualify, and it costs less to learn that now than after the stock is boxed.
• Run each ASIN through the Revenue Calculator. The calculator on Amazon's FBA page compares estimated costs for FBA against fulfilling the same order yourself. Amazon's marketing claims FBA shipping costs run 70% less per unit than comparable premium options from other major US carriers, and the calculator is where you test that claim against your own catalog.
• Know the fee categories by name. There are six:
  • Fulfillment fees, charged per unit and priced by the item's dimensions, weight, and price.
  • Monthly storage fees, computed on the daily average cubic feet your inventory occupies.
  • An aged-inventory surcharge on units stored 181 days or longer.
  • Returns processing fees.
  • Per-item removal, disposal, and liquidation charges.
  • The FBA inbound placement service fee.
  Rates vary by product and change over time, so treat the Revenue Calculator as the source of the numbers you'll actually pay.
• Confirm the selling plan fits your volume. FBA works on both the Individual and Professional plans, and Amazon frames FBA as likely more cost-effective once you're moving more than 40 items a month on the Professional plan. Check where your volume sits before converting a large catalog.
• Decide who labels your units. Stock in Amazon's fulfillment centers needs an FNSKU label on each unit, plus packaging that meets FBA's prep guidelines. You can print FNSKU labels from Seller Central and apply them yourself, or pay Amazon a per-unit fee to do the labeling. The conversion flow will ask you to choose, so settle it now.

Step 1: Enable FBA on the account you have

Switching does not mean opening a second account. Existing FBM sellers enable FBA on their current Seller Central account, and if yours has never used FBA, the registration path is short: click the gear icon, choose Account Info, click Manage on the Seller Account Information page, then choose Register for FBA. If FBA is already enabled on your account, skip straight to the conversion.

Step 2: Convert the listings in Manage Inventory

As of August 2026, the conversion click-path runs:

1. Open Manage Inventory in Seller Central.
2. Select the products to switch. The checkboxes support bulk selection, so an entire batch of SKUs converts in one pass.
3. Open the Edit dropdown and choose Change to Fulfilled by Amazon.
4. Pick your barcode type. This is where the labeling decision from the pre-flight list applies: your own printed FNSKU labels, or Amazon's paid labeling.
5. Click Convert & Send Inventory to finish the conversion and continue into the shipment workflow.

Amazon revises Seller Central regularly, so if a button label has drifted from what's written here, follow the on-screen flow; the order of the steps is the stable part.

Step 3: Send the inventory with Send to Amazon

Converting a listing changes who will fulfill it, but the stock still has to reach Amazon, and Send to Amazon is the workflow that gets it there. It walks you through preparing, packing, and labeling the shipment, and asks you to settle the following:

• Packing format. Individual units or case packs. For case packs, you create a template that records the units per box, the box dimensions in inches, and the box weight in pounds, then enter how many boxes you're shipping.
• Expiration dates, for product categories that require them.
• Ship date and mode. Pick the date the shipment leaves, and whether it travels as small parcel delivery (SPD) or as less-than-truckload (LTL) palletized freight.
• Carrier. Choose an Amazon-partnered carrier (UPS, as of this writing) or a non-partnered carrier such as FedEx or USPS, then review and accept the shipping charges.
• Labels. Print the box labels and the shipping labels from the workflow and apply them before handing the boxes off.

Once the shipment is on its way, it appears in your shipping queue in Seller Central, and that queue is where you track its progress. If you're curious what happens after the truck door closes, our post on how an Amazon fulfillment center works follows the inventory through the other side.

What changes after the switch

• The fulfillment work leaves your desk. Amazon picks, packs, and ships orders on converted listings.
• Customer service and returns for those orders move to Amazon. Our guide to returns, refunds, and damaged or lost products for FBA sellers covers how that handoff works in practice.
• The Prime badge arrives. FBA offers are eligible for Prime, with free two-day shipping for Prime customers.
• Storage becomes a metered cost. Monthly storage fees accrue on daily average cubic feet, and the aged-inventory surcharge starts at 181 days in storage. Put a recurring inventory-age check on your calendar the week you send your first shipment; slow movers now cost money while they sit.

If a multichannel tool manages your listings

One caution for sellers who list through a multichannel management tool: make the fulfillment change inside the tool and let it sync to Amazon. Sellbrite, for example, has sellers change the Fulfilled By setting on a listing's Offer tab, supports bulk editing and offer templates for larger catalogs, and warns in its help documentation that switching directly in Amazon can create ghost listings and inventory sync problems between the tool and the marketplace. Whatever tool sits between you and Seller Central, look up its switch procedure before touching Manage Inventory directly.

FAQ: switching to FBA

Do I need a new Amazon account to use FBA?

No. FBA is enabled on the Seller Central account you already sell from. If the account has never used FBA, register via the gear icon, then Account Info, then Manage, then Register for FBA.

Can I switch a listing back to FBM later?

Yes, a listing's fulfillment type can be changed in the other direction as well. Before you do, remember that getting unsold stock back out of a fulfillment center is what the per-item removal and disposal charges cover, so run down your FBA inventory before flipping a listing back.

What does switching to FBA cost?

Six fee categories apply: per-unit fulfillment fees set by the item's dimensions, weight, and price; monthly storage billed on daily average cubic feet; an aged-inventory surcharge from 181 days in storage; returns processing fees; per-item removal and disposal charges; and the inbound placement service fee. Rates vary by product and change over time, so run each ASIN through the Revenue Calculator for numbers you can plan around.

How do I label products for FBA?

Each unit needs an FNSKU label and packaging that meets FBA prep guidelines. Print the labels from Seller Central and apply them yourself, or pay Amazon a per-item fee to label the units for you; the conversion flow asks which you want.

Start with the Revenue Calculator on Amazon's FBA page: run your top FBM ASINs through it, and if the estimates beat what you spend fulfilling those orders yourself, work through the pre-flight list and then down the three steps. Once the homework is done, the switch itself is a short Seller Central session followed by one carefully packed shipment.