FBA vs FBM Calculator

The comparison every fee table tells you to "model yourself" - modeled. Per-unit costs for both routes, plus the part that actually decides it: what the Prime badge does to your monthly volume. 100% free, no signup, and every figure you enter stays in your browser.

Both columns are built from the costs entered above. Selling-plan fees, media closing fees, long-term storage and aged-inventory surcharges, removals, return-processing labor, and tax fall outside this comparison - they hit the two routes differently, so check them before a switch.

What this comparison actually involves

Most fee tables end with a paragraph telling you to "model both options for your product." Here's what that modeling has to include, and what this page computes:

• Both routes pay the referral fee. FBM isn't fee-free - it swaps Amazon's fulfillment and storage fees for postage, packaging, labor, and your own space.
• Your labor is a cost. Four minutes a package at $20/hour is $1.33 per order. At 200 orders a month that's ~13 hours of packing - count it, or FBM's "savings" are partly you working an unpaid job.
• The Prime badge changes volume, not just cost. Per-unit profit alone can crown the wrong winner: FBM often looks better per unit while FBA earns more per month, because the badge converts more of the same traffic. The breakeven lift in the verdict is the number that settles it for your product.
• Season matters. FBA storage roughly triples in Q4; FBM postage rises with carrier peak surcharges. Re-run the comparison with peak numbers before the holidays.

Frequently asked questions

Is FBA or FBM more profitable?

Product by product. Per unit, FBM often wins on paper - postage plus packaging plus labor can undercut Amazon's fee, especially for large or slow items. Per month, FBA often wins anyway because the Prime badge converts more of the same traffic. This calculator multiplies both sides out so you compare monthly profit, not per-unit illusions.

Do FBM sellers pay Amazon fees too?

Yes - every sale pays the referral fee (15% in most categories, see the fee tables) plus any selling-plan fee. FBM only skips the fulfillment and Amazon-storage fees.

How much does the Prime badge increase sales?

Amazon doesn't publish it, and it genuinely varies - by category, price, and competition. That's why the lift is your input here, and why the verdict reports the breakeven lift: if your realistic estimate clears it, FBA wins for your numbers.

Can I use FBA and FBM at the same time?

Yes, in two different ways. Across products, run FBA for small fast-turners and FBM for large or slow items. On a single product, list the same ASIN twice under two SKUs - one fulfilled by Amazon, one by you - so both offers sit on the same listing. You do not have to pick a route per business, or even per product.

Sellers usually name the pair so it reads at a glance, like WIDGET-BLUE for the FBM offer and WIDGET-BLUE-FBA for the FBA one. That also gives you the cleanest possible version of this comparison: two routes on the same listing, same traffic, same price, with only fulfillment different. Amazon surfaces one offer at a time and the FBA offer normally takes the buy box, so the FBM offer works as backup - it keeps the listing live while a shipment is in transit or FBA stock hits zero, instead of you flipping the listing back and forth.

One trap worth knowing before you try it: the new SKU does not join your existing advertising campaigns automatically. Add it yourself, either into the same ad group to share keyword history, or into its own so you can read each route's conversion separately.

Is this comparison free, and does my cost data stay private?

Free with no account and no API key, and your data stays with you. The whole comparison - both routes, the monthly rollup, the breakeven lift - is computed client-side in your browser. Your landed cost, postage rates, and labor figures are never uploaded or stored on a server. See the privacy policy.