When should I switch from FBA to FBM?
Switch a SKU from FBA to FBM when it costs more in FBA fees than it earns in Prime-badge conversion lift. Common triggers: oversize items where FBA fees exceed 40% of price, slow movers accumulating storage fees, and SKUs with high return rates that never break even after refund reserve.
The four SKUs to move to FBM first
Oversize items with FBA fees above 40% of price. Slow movers aged 90+ days paying storage fees. High-return SKUs where refund reserve wipes out margin. Low-price items ($10 or under) where FBA fee is 60%+ of price.
What FBM costs you
You lose the Prime badge on most SKUs (Seller Fulfilled Prime is available but selective), which typically drops conversion by 20% to 40%. You take on shipping, packing, customer service, and returns. Do the math on labour before switching.
Hybrid approach
Keep top movers on FBA for the Prime badge. Move oversize, slow, or high-return SKUs to FBM. Many mature accounts run 70% FBA / 30% FBM by unit count.
Frequently asked questions
Does FBM lose the Buy Box?
FBM competes for the Buy Box, but at a disadvantage against FBA on price parity. Prime-eligible FBM (SFP) closes some of the gap.
Are FBM sellers still eligible for Prime?
Only through Seller Fulfilled Prime, which has strict performance requirements and is not always accepting new sellers.
Does Nova P&L cover FBM SKUs?
Yes. Nova is FBM-inclusive: SKU-level profit calculations work for both fulfilment types.
How fast can I switch a SKU?
Change the fulfilment method in the listing, then submit a removal for FBA units. Full cutover typically takes 2 to 3 weeks.
See this in Nova
Nova surfaces this metric per SKU in near real time so you can act before your next monthly close catches it.
Try Nova free for 14 daysRelated questions
How do I forecast Amazon demand accurately?
The most accurate simple forecast weights the last 30 days at 60% and the prior 60 days at 40%, then adjusts for seasonality and known promotions. For most private-label SKUs this beats gut-feel and matches what statistical models produce within a 10% margin. Rebuild the forecast every 2 to 4 weeks.
How do I avoid FBA storage limits?
FBA storage limits are set by IPI score. Keep IPI above 400 by clearing stranded inventory weekly, running removals or liquidations on units aged 180+ days, and keeping your top 20 SKUs consistently in stock. Restock-limited accounts often gain 30% to 60% more capacity within 30 days after a targeted cleanup.
What triggers Amazon's aged inventory surcharge?
Amazon's aged inventory surcharge applies on top of monthly storage fees for units aged 271+ days in FBA. Rates start around $1.50 per cubic foot and climb sharply at 365 days. The fastest way to avoid it is a removal order or a targeted price cut before day 270.
Are Amazon returns deducted from seller payouts?
Yes. When a customer returns an FBA order, Amazon refunds the buyer and deducts the refunded amount from your next payout. Amazon also refunds most of the referral fee (keeping a $5 or 20% refund administration fee, whichever is lower) but does not refund the FBA fulfilment fee. Returns can also trigger a returns processing fee in apparel and shoes.
How do I find hidden Amazon fees eating my margin?
The fees that hurt most are rarely hidden, they are just scattered across multiple Seller Central reports. Check monthly storage, aged inventory surcharges, low-inventory-level fees, inbound placement fees, returns processing, subscription-and-save discounts, and coupon redemption fees. Rebuilding a per-SKU P&L from the Fee Preview and Payments reports usually reveals a 3 to 8 point margin gap.