FREE PROFIT CALCULATOR

FBA vs FBM vs Seller Fulfilled Prime Profit Calculator

Which Amazon fulfillment method makes the most profit per unit? For most small, steady-selling products it is Fulfillment by Amazon (FBA): one fee covers picking, packing, shipping and customer service, and the Prime badge helps conversion. Fulfillment by Merchant (FBM) and Seller Fulfilled Prime (SFP) often win on oversized, heavy, high-value or slow-moving products, or when FBA capacity limits cap your stock. Enter your own numbers to see all three side by side.

By Andrew Morgans, founder of Marknology  |  Updated September 2026

Every default below is an example, not Amazon's fee schedule. Enter yours. Results update as you type.

Product and selling costs (all methods)

Example values. Enter yours.

Fulfillment by Amazon (FBA)

Example values, not Amazon's rate card. Get your real fees from the Revenue Calculator or the Fee Preview report in Seller Central.

Your own warehouse or 3PL (FBM and SFP)

Example values. Use your warehouse or 3PL quote, including postage.

FBA
Fulfillment by Amazon
Profit per unit
--
Margin --
FBM
Fulfillment by Merchant
Profit per unit
--
Margin --
SFP
Seller Fulfilled Prime
Profit per unit
--
Margin --
Cost per unit FBA FBM SFP
Referral fee -- -- --
Product cost -- -- --
Fulfillment -- -- --
Storage -- -- --
Inbound, receiving and prep -- -- --
Returns -- -- --
Advertising -- -- --
Total cost per unit -- -- --

How it works: profit per unit is price minus product cost, referral fee, fulfillment, storage (monthly storage times months in stock), inbound or receiving, returns and advertising. Returns cost is the return rate times the fulfillment cost plus the share of returned product you cannot resell. Margin is profit divided by price. It does not include the Prime badge's effect on sales, aged inventory surcharges, low inventory fees, or SFP program fees; add any that apply to the matching cost line.

WHEN EACH WINS

When does FBA, FBM or Seller Fulfilled Prime win?

FBA: the default

Start here for small and standard size products that sell steadily. Amazon's network delivers fast nationwide, handles returns and customer service, and the Prime badge helps you convert and win the Buy Box. Watch storage and aged inventory fees on slow sellers, especially from October through December.

FBM: big, custom or slow

Ship it yourself when FBA fees break the unit economics: oversized and heavy items, made-to-order products and slow movers that would pay storage for months. FBM is also a smart backup offer on key products so a stockout at Amazon does not stop sales. The trade-off is no Prime badge.

SFP: Prime from your warehouse

Use it for oversized, heavy or high-value products that need the Prime badge, when FBA capacity limits cap your stock, or when you want one inventory pool for Amazon, Shopify, Walmart and TikTok Shop. It only works if you or your 3PL can hit Amazon's delivery, tracking and weekend shipping standards every week.

SIDE BY SIDE

FBA vs FBM vs Seller Fulfilled Prime compared

Amazon adjusts fees and program rules regularly. Confirm current details in Seller Central before you switch a product.

FBA FBM Seller Fulfilled Prime
Who stores and ships Amazon You or your 3PL You or your 3PL
Prime badge Yes No Yes, after your account passes the SFP trial
What Amazon charges Referral fee, fulfillment fee, monthly storage, inbound placement and related fees Referral fee Referral fee, plus any SFP program fees Amazon applies
What you pay directly Freight to Amazon and prep Warehouse, labor, packaging and postage Warehouse, labor, packaging and faster postage
Delivery standards Handled by Amazon's network Standard seller metrics Strict: on-time delivery, valid tracking, cancellations and weekend shipping
Customer service after the order Amazon You Amazon
Inventory A separate pool inside Amazon, subject to capacity limits One pool you control One pool you control, shared with your other channels
Usually wins for Small and standard size products that sell steadily Oversized, custom or slow-moving products, and backup offers Oversized, heavy or high-value products that need Prime, and brands capped by FBA capacity limits

Go deeper: our FBA vs FBM decision framework, how Seller Fulfilled Prime works with a 3PL, every Amazon seller fee explained, how much a 3PL costs, and what our FBA prep center in Kansas City handles now that Amazon no longer preps inventory for you. To estimate the FBA fee itself from size and weight, use our FBA fee calculator.

Want Prime without sending everything to FBA?

We run our own 20,000 square foot warehouse in Kansas City, and it is approved for Seller Fulfilled Prime. Orders received by noon Central ship the same day, and the same stock can serve Amazon, Shopify, Walmart and TikTok Shop. If the numbers above point to SFP for some of your products, see how our warehouse works, or bring your top products to a free 30-minute strategy call and we will run them with you.

Book a Free Strategy Call
FAQ

Frequently Asked Questions

Is FBA or FBM more profitable?

It depends on the product. For small, standard size products that sell steadily, FBA is usually more profitable once you count the conversion lift from the Prime badge. For oversized, heavy, slow-moving or custom products, FBM often keeps more per unit because FBA fulfillment and storage fees rise with size and time in stock. Run each product through the calculator above with your real fees.

What is Seller Fulfilled Prime?

Seller Fulfilled Prime (SFP) is an Amazon program that lets a seller show the Prime badge on orders shipped from its own warehouse or a 3PL instead of Amazon's fulfillment centers. Your account has to pass a trial and then keep meeting Amazon's standards for on-time delivery, valid tracking, cancellations and delivery speed. Check the current requirements on the SFP page in Seller Central.

Is Seller Fulfilled Prime cheaper than FBA?

Sometimes. SFP usually costs more per shipment than regular FBM because orders must arrive fast, but for oversized, heavy or high-value products it can cost less than FBA fees and storage while keeping the Prime badge. For small, fast-selling items, FBA is usually competitive. Compare both with a real month of your orders.

Where do I find my actual Amazon fees?

Use Amazon's Revenue Calculator, which Amazon links from its selling fees page, and the Fee Preview report in Seller Central for the fees Amazon expects to charge on each of your products. Amazon changes fees regularly, so enter current numbers rather than the example values on this page.

Does this calculator include the effect of the Prime badge on sales?

No. It compares cost and profit per unit only. Offers with the Prime badge, whether FBA or SFP, often convert better than FBM offers without it, so a method with lower profit per unit can still make more total profit. Test the difference on your own listings.

Can I use FBA and Seller Fulfilled Prime at the same time?

Yes. Many brands keep FBA for most of the catalog and use SFP for oversized products or as a backup offer when FBA stock runs low or capacity limits cap what they can send in. Each offer needs its own SKU and its own inventory.