Amazon FBA vs FBM Calculator (2026)

FBA (Fulfilled by Amazon) means you ship inventory to Amazon's warehouses and they pick, pack, and ship each order — you pay a fulfillment fee plus monthly storage. FBM (Fulfilled by Merchant) means you store and ship every order yourself — you pay your own shipping and packing labor instead, and typically lose Prime eligibility unless you qualify for Seller Fulfilled Prime.

No — the referral fee is based on category and price, and applies identically whether Amazon or you fulfill the order. This calculator applies the same referral fee to both columns so the comparison isolates just the fulfillment-cost difference.

Time yourself packing 5–10 real orders and average it, including printing the label and walking to a drop-off point if that's part of your routine. Most small sellers land between 3–10 minutes per order depending on product complexity. Multiply that by what your time is actually worth — even if you're not paying yourself a wage today, this shows the true opportunity cost.

This calculator only compares per-unit and monthly fee profit — it doesn't model the sales-velocity boost Prime eligibility gives FBA listings, or the storage and long-term storage fees that stack up on slow-moving FBA inventory. A slim FBA win on paper can turn into an FBM win in practice if your item is bulky, seasonal, or slow-turning.

Yes — many sellers run both offers on the same ASIN (or a similar one), keeping fast movers in FBA for the Buy Box advantage and using FBM as overflow capacity or for oversized/low-velocity SKUs where storage fees eat into margin.