Amazon changed the rules again.
This year, when you build an FBA shipment plan, the system splits your inventory across three warehouses by default. The "combined shipment" option is buried deeper in the page than ever, and the inventory placement fee keeps creeping up. My seller group chats are full of the same question every week: split or combined — which one actually saves money?
Short answer: there is no universal answer. But there are three calculations. Run them, and you'll know which one fits your situation.
Quick glossary for anyone still fuzzy on the terms: a split shipment plan breaks your freight into multiple legs, each going straight to a different Amazon fulfillment center. A combined plan sends everything to a single FC — you pay a placement fee, and Amazon handles the rest of the redistribution itself. One pushes the hassle forward (you run more inbound legs), the other pushes it backward (you bet on Amazon's internal transfer network).
Calculation 1: How Much More Does Inbound Freight Cost on a Split Shipment Plan?
Last year, ahead of Black Friday, we shipped 300 cartons — roughly 6,000 units — out of our Los Angeles 3PL warehouse. The shipment plan came back with three destinations: one FC in California, one in Arizona, one in Texas.
Our forwarder quoted two options. Option A, split: three separate direct shipments, 100 cartons each. Option B, combined: all 300 cartons to the California FC in one shot, letting Amazon redistribute internally, plus a placement fee.
Here's our store's actual data from that shipment: the three split legs cost about 18% more in total inbound freight than the single combined load. The math is boring — three bookings, three sets of paperwork, three delivery appointments. Fixed per-shipment costs don't scale down. The bigger your volume, the smaller the gap; the smaller your volume, the more split shipments hurt.
Zoom in and it's clearer: each of the three legs carried a few hundred dollars in fixed charges — booking, documentation, pickup — that don't change whether you ship 100 cartons or 300. Split a small batch and you're paying those fixed costs three times over.
Heads-up for smaller sellers: if you've only got 50 cartons and you insist on splitting across three FCs, each leg is a tiny LTL nobody wants to haul. Your per-carton cost goes through the roof. At that volume, just combine.
Calculation 2: The Placement Fee Looks Expensive — Internal Transfers Can Cost More
This is the calculation most sellers get wrong.
A combined shipment carries a placement fee. It's printed right there on the screen, and it stings. But here's what split shipments hide: Amazon redistributes your inventory between its own warehouses anyway. Your stock sits in California, a buyer in Texas orders, and Amazon has to move units from California to Texas. That transfer cost never shows up on your invoice — it shows up as two things instead: slower availability and split customer shipments.
We learned this the hard way this March. We combined 300 cartons into California to save the hassle. Amazon's internal transfer took 12 days to spread inventory to the East Coast FCs. We stocked out in the eastern US for a full week while our ads kept running. ACOS shot past 40%. The profit we lost that week would have covered several rounds of placement fees.
Here's the counterintuitive part: the placement fee is a visible cost; a split shipment's hidden costs are invisible. Splitting doesn't automatically save money — the placement fee you "saved" can come back doubled as stockout losses from transfer delays. And if your sales concentrate in one region, splitting actually forces Amazon to transfer more, not less.
How much is the placement fee, exactly? Don't ask me — ask Amazon. When you build the shipment plan, the rate is shown right next to the combined option. And remember: it changes. Always go by Amazon Seller Central's latest policy, not last year's screenshot.
Calculation 3: Speed Is Money — Do Your Own Stockout Math
The third calculation is the simplest and the most painful.
Split shipments: freight goes straight to three FCs, each checks in on its own, and you're live nationwide fast. Last year's split shipment went from our 3PL to all three FCs available-for-sale in 9 days.
Combined: inventory lands at one FC, checks in fast (single receiving appointment), but nationwide coverage waits on Amazon's internal network. That March shipment was sellable at the single FC in 5 days — but full US coverage took 17 days.
So the speed calculation goes like this: launching a new product and chasing rank? Split shipments buy you nationwide availability, and that's worth real money. Replenishing a steady evergreen SKU? A combined shipment's fast single-FC check-in is simpler and fine. For peak-season inventory, my rule is always split — never gamble on Amazon's transfer speed when it matters most.
Split vs. Combined: The Comparison Table (Our Store's Real Numbers)
| Split Shipments | Combined Shipment | |
|---|---|---|
| Inbound freight | Three direct legs, about 18% more in total | One load to one FC, cheapest freight |
| Placement fee | None | Per Amazon Seller Central's latest policy — check before you book |
| Single-FC check-in speed | Three separate receiving appointments, slightly slower | One appointment, fastest to sellable |
| Nationwide availability | Fast, about 9 days to all FCs sellable | Slow, depends on internal transfers — ours took 17 days |
| Stockout risk | Low, inventory spread out | High, transfer delays can strand regions |
| Best for | Peak-season stock, new launches, 300+ cartons | Routine replenishment, mature SKUs, small batches |
One important note: placement fee rates change — always check Amazon Seller Central's latest policy before you run your numbers. Don't trust last year's fee schedule.
Pitfalls: Six Things Not to Do
First, don't split small batches. Under 100 cartons split three ways, the per-leg cost is brutal. Combined is the only sane choice.
Second, build peak-season shipment plans 45 days out. Split or combined, give yourself time. Building your Black Friday plan in September is a lost cause no matter which option you pick.
Third, don't stare at the placement fee alone. Add up the freight difference and the stockout cost of transfer delays. Total all three calculations before deciding.
Fourth, if your sales concentrate in one region, stop overthinking it. When 70% of our orders ship to the East Coast, we split with the bulk going to the eastern FC. Nothing beats that.
Fifth, don't blindly accept the system's recommended split. The three FCs Amazon suggests aren't always the optimal combo. Tweak it manually — put the bulk near where your buyers actually are, and let the rest ride.
Sixth, check your sales map before mixing multiple SKUs in one plan. Different SKUs can have completely different hot regions. One plan for two different demand patterns is a recipe for a stockout. Build per-SKU plans — five extra minutes of hassle, a whole season of peace.
Our store's SOP now is dead simple: 300+ cartons for peak season go split, routine replenishment goes combined, small batches always combined. A year on this rule — zero stockouts, lower inbound costs.
This one I've personally tested. Steal it and use it.
By Ah K, E-commerce Seller (5 yrs)
