← Amazon FBA vs FBM calculator
Sellers search this after a supplier quotes a lower unit cost only at 300, 500, or 1,000 pieces. The cheaper COGS is only half the decision. The bigger pile sits in FBA until it sells, so storage rises, inbound may fall, and more cash is tied up before the first extra dollar of leftover comes back.
Open the Amazon FBA calculator, keep your own list price and fee preview, and enter the usual PO quantity, the MOQ, and the MOQ unit cost. Leave months blank to scale the listing stay by pile size. The table below uses the page defaults: $29.99, 15% referral, large-standard FBA at $4.15, $8.00 usual cost, $1.20 inbound, one month of storage on a 100-unit PO, 80 units a month, 30% target margin, and a 500-unit MOQ at $6.50 with $0.90 inbound.
The usual 100-unit PO keeps $10.99 (36.7%) and hits the 30% target. The 500-unit MOQ at $6.50 sits 5.0 months (5× the usual stay) and keeps $12.60 (42.0%) — $1.61 more per unit, $803.33 more on the pile. That still hits the target. Extra cash on the MOQ is $3335.95. The MOQ unit cost can rise to $8.11 before the usual PO wins. At 80 sales a month that extra cash pays back in about 26.0 months.
| Order | COGS | Months | Profit | vs usual |
|---|---|---|---|---|
| Usual PO (100 units) | $8.00 | 1.0 | $10.99 | $0.00 |
| MOQ PO (500 units) | $6.50 | 5.0 | $12.60 | +$1.61 |
If the MOQ is the same $8.00 cost and the same $1.20 inbound, only extra storage is left. The 500-unit pile then keeps $0.19 less per unit. A still-cheaper inbound or a still-cheaper COGS has to cover that stay. The calculator reports the MOQ cost that ties the usual PO — $8.11 on the discounted example above, or $7.81 when cost and inbound stay put and only the pile grows.
This is not a leftover-unit hold-or-remove decision and it is not a coupon. Rates change by category, size, season, and account. This page does not publish Amazon’s live storage or inbound schedule. Enter the numbers from your current fee preview. The calculator is arithmetic, not advice, and it does not claim a larger PO will sell through on the months you typed.
On the calculator example — a $29.99 home listing, 15% referral, large-standard FBA at $4.15, and an $8 usual buy — a 100-unit PO keeps $10.99 (36.7%). A 500-unit MOQ at $6.50 with $0.90 inbound sits 5.0 months and keeps $12.60 (42.0%), $1.61 more per unit and $803.33 more on the pile. It also ties up $3335.95 extra cash. The MOQ unit cost can rise to $8.11 before the usual PO wins, and that extra cash pays back in about 26.0 months of sales at 80 units a month.
Then only extra storage is left. On this example a 500-unit pile at the same $8 cost and $1.20 inbound sits 5.0 months and keeps $0.19 less per unit than the 100-unit PO. The cheaper inbound and the cheaper COGS have to cover that stay — the calculator shows the MOQ cost that still ties.
No. Referral and fulfillment stay the same on each sale. Inbound can fall on a full carton, and storage rises because the pile sits longer. The page scales the listing months by MOQ ÷ usual quantity unless you type a stay. It does not recommend taking the MOQ.