Am I paying a placement fee I do not need to pay?
Compare "ship to 1 FC and pay the fee" against splitting across 2 to 5 FCs for this specific shipment. Shows which is cheaper and by how much.
Open placement-fee calculator →Inbound shipment optimizer
Every route.
Every fee.
The cheapest legal way to ship your next FBA shipment.
We run placement fee, split-ship, and 5-identical-carton — and tell you which wins for the shipment in your hand.
Reads the current 2026 Amazon fee schedule, version-stamped. Works without an Amazon login. No card required to use the calculators.
Split-ship wins for varied SKUs, saves $37.
Your shipment
47 units · 12 SKUs · 22 lb
5 cartons · 22×16×12 in
8 units · 3 SKUs · 4 lb
Placement fee · 1 FC
Saves$12
$84
$112
$12
Split-ship · 3 FCs
Saves$37
$47
$84
$24
5-identical-carton · zero fee
not eligible
Saves$84
not eligible
N/A
$0
N/A
Illustrative scenarios. Actual savings vary by shipment.
Try a shipment:
Three questions. Three calculators. No signup to get the number.
Each one answers a question sellers are already running by hand, or not running at all.
Does this shipment qualify for the zero-placement-fee path?
Amazon waives all placement fees on shipments of ≥ 5 identical cartons. Three conditions, often missed. Savings on a 1,000-unit large-standard shipment: $550 to $1,900.
Open 5-Carton checker →Is this product actually in the size tier you think it is?
Add prep padding (bubble wrap, poly bag). See the packed dimensions Amazon will use for fee lookup. Flags products within one inch of a tier boundary before the overcharge lands.
Open size-tier checker →2026 changed the math. Your spreadsheet did not.
Amazon shipped two fee events in the first four months of 2026. The January 15 FBA restructuring (weight bands, split size tiers, defect fees up 16× on some SKUs) and the April 17 fuel surcharge (a 3.5% multiplier on fulfillment fees). Placement-fee decisions that used to be "close enough" now compound into real money on every inbound.
Placement fees are a (not so) silent killer in my business. My small SPD cartons cost way more than planned and my landed cost per unit jumped so much it killed my promo.
Amazon's own packing endpoints have been broken since 2024. The math falls back on the seller. CrateFit does the math.
Catalog in, shipment out, receipt attached.
Add your SKUs once.
Manually or via Amazon's Active Listings Report CSV. Dimensions, weight, prep requirements. CrateFit computes packed dimensions and flags any SKU within one inch of a size-tier boundary.
Build the shipment.
Pick which SKUs, how many units, which box sizes you have on hand. CrateFit runs multi-SKU 3D bin-packing against Amazon's per-carton constraints (36" max length, 25" max width/height, 50 lb max weight).
Get the cheapest legal path.
A summary bar up top (total boxes, total weight, savings in amber). A strategy comparison underneath (1 FC placement vs split-ship vs 5-identical-carton). A collapsible box-by-box breakdown. A printable packing sheet for the warehouse wall.
Every dollar is a line item.
Every result ships with an expandable receipt. DIM weight × units, base fulfillment by weight band, placement fee or split-ship freight, April 2026 fuel surcharge on fulfillment fees only. Plus a fee-schedule version stamp showing the exact Amazon rates used. If the number does not match your spreadsheet to the cent, something is wrong. Tell us and we will fix it.
Receipt example · large standard, 14 lb · 1,000 units
- Large standard, 14 lb — base fulfillment
- $8.00
- Fuel surcharge (Apr 17, 2026, 3.5%)
- $0.28
- DIM weight charge
- $0.00
- Placement fee (1 FC, minimal shipments)
- $0.55
- Per unit
- $8.83
- × 1,000 units
- $8,830.00
Fee schedule: 2026-04-fuel · view version →
Amazon changed fees twice this year. CrateFit reflected both without a release.
Fees live in a versioned data table. Every calculator reads the current version by default. Every saved shipment is stamped with the version it used. When Amazon ships the next surprise, CrateFit updates the table and every past result stays reproducible. View fee schedule →
What other tools optimize (and what they do not).
| Tool | Inventory tracking | Multi-SKU box optimization | Placement-fee comparison | 5-Carton detection | Price |
|---|---|---|---|---|---|
| CrateFit | — | ✓ | ✓ | ✓ | $19 to $25 / mo |
| Boxem | ✓ | — | — | — | $42 to $69 / mo |
| InventoryLab | ✓ | — | — | — | $49 to $69 / mo |
| ShipSavy (Apr 2026) | — | Single-SKU only | — | — | $29 / mo |
| Generic 3D bin-packing APIs | — | Spatial only | — | — | Varies |
Incumbents are inventory software with a packing sidecar. CrateFit is the packing and routing decision, priced under half.
The app ships next. Be first in.
The free calculators are live now. The authenticated app (saved catalog, shipment history, CSV import, printable sheets) ships next. Waitlist gets the first invites and a founding-member price lock on the current $19 to $25 tier.
No marketing spam. One email when calculators add features, one email when the app opens.
Frequently asked questions
What is CrateFit?
CrateFit is an Amazon FBA inbound shipment optimizer. It reads your catalog and a shipment, runs multi-SKU 3D bin-packing against Amazon's per-carton constraints, and returns the cheapest legal placement strategy with a line-item fee receipt. Three free public calculators cover placement fees, the 5-Carton Rule, and packed-dimension size-tier classification.
How much does CrateFit cost?
$19 to $25 per month with a 14-day free trial. Card collected up-front at signup via Stripe Checkout. Competitors charge $42 to $69 for workflow tooling that does not optimize placement. Founding-member price lock for waitlist signups.
Is CrateFit affiliated with Amazon?
No. CrateFit is independent. Amazon receives none of our revenue and we receive none of theirs. The tool reads Amazon's published fee schedule and applies it to seller-entered catalog data.
Do I need to connect my Amazon account to use CrateFit?
No. The calculators work on dimensions, weights, and counts you enter directly. When the paid app opens, SP-API connection is optional, not required.
What FBA fees does CrateFit calculate?
Base fulfillment (by weight band), DIM weight charges, placement fees (1 FC vs split-ship), the April 17, 2026 fuel surcharge (3.5% on fulfillment fees only), and the 5-identical-carton zero-placement-fee path. Referral fees and storage fees are not in scope for v1 since they do not change with packing decisions.
Why should I trust your fee math?
Every number is a line item on an expandable receipt, with the Amazon fee version stamped on the result. Reproduce it in your spreadsheet. If anything is off, we want to know.
What happens if Amazon's packing endpoints start working?
We will use them where they help. The endpoints have been documented as broken since 2024 (GitHub #5006). We do not plan the product around them turning on.
Is CrateFit for enterprise sellers too?
CrateFit is built for individual sellers and brands shipping 100+ units a month across 10+ SKUs. Larger operators are welcome. 3PLs running Sellercloud already have different tooling at a different price point.