Methodology and sources

Status labels

• Amazon A rate Amazon publishes. Read from Amazon directly, or, where Amazon's page needs a sign-in, cross-checked across at least two independent copies of the same rate card that agree to the cent.
• Derived Computed from published rates by a stated rule. The holiday peak card is derived: 2026 non-peak fee + 2025 peak increment (Amazon: increment unchanged vs 2025). Reproduces all 9 published 2026 peak data points.
• Estimate Our assumption with no published confirmation. Currently: peak increments for apparel and dangerous goods beyond the first row (we use the standard increment), and the average bulky packaging fee for items not certified Ships in Product Packaging ($2.07).
• Yours Inputs you control: product cost, freight, ads, returns.

Calculation rules

1. Sides are sorted longest to shortest. Length plus girth = longest + 2 × (median + shortest).
2. Dimensional weight = L × W × H ÷ 139. Bulky and extra-large use at least 2 in for width and height.
3. Tier = the smallest tier whose side, girth and weight limits all fit, using the greater of unit and dimensional weight.
4. Billed weight: unit weight for small standard and extra-large over 150 lb; otherwise the greater of unit and dimensional weight.
5. Weight rows are “over the lower bound, up to and including the upper bound”. Per-step charges (4 oz for large standard over 3 lb, 1 lb for bulky and extra-large) count any partial step as a full step.
6. Price band: under $10.00, $10.00 to $50.00, over $50.00, on the item price.
7. Peak applies to ship dates from 2026-10-15 to 2027-01-14 inclusive. The 3.5% surcharge applies from 2026-04-17 to the fee after any peak increment. We round the surcharged fee to the nearest cent; Amazon doesn't publish its rounding, so single-cent differences are possible.
8. Referral fee: flat, whole-price threshold or portion-based, as published, with the per-item minimum. Media adds a $1.80 closing fee.
9. Storage = unit volume in cubic feet × monthly rate for the ship date's season × months in storage.
10. Returns allowance = return rate × unsellable share × landed cost (product + freight + prep). A simplification; see below.

Not modeled yet

• Overmax handling fee amount (reported as $17–$25 per unit; we warn instead of adding it)
• Storage-utilization surcharge (depends on your whole account, not one product)
• Inbound defect fees and liquidation fees
• New Selection program referral credits and other incentives
• Dangerous-goods storage rates (hazmat storage costs more per cubic foot than standard)
• Remote Fulfillment to Canada, Mexico and Brazil

Tests

The fee engine runs automated tests on every change, including:

• Amazon's 2026 examples: mobile case $2.49 → $2.68 peak; baby cot (small bulky) $10.21 → $11.25; TV (extra-large 50–70 lb) $48.57 → $51.38.
• Published 2026 peak figures: $2.62 / $3.51 / $3.77, $4.07, $5.34 and $7.51.
• A $190 tool at 1–1.25 lb in the over-$50 band: $5.30 × 1.035 = $5.49, matching a live Amazon fee readout published by Apex Applications.
• Dimensional weight examples from Amazon partners (16 × 12 × 8 in → 11.05 lb; 44 × 9 × 35 in → 99.71 lb, extra-large).
• Referral thresholds: Grocery at $15.00 vs $15.01, Clothing at $20.00 vs $20.01, portion tiers for Electronics Accessories, Jewelry, Furniture and Watches.

Sources

• Amazon Seller Central: FBA fulfillment fees (2026 US rate card) — Read directly on 2026-10-18 (non-peak, peak, apparel and dangerous goods tables). Earlier cross-checks: BQool (Dec 30 2025), TechMachaw (Sep 6 2026).
• Amazon Selling Partners: Update to U.S. Referral and Fulfillment by Amazon fees for 2026
• Sell on Amazon: Standard selling fees (referral fees) — Fetched directly 2026-10-18.
• Amazon Seller Central: Product size tiers
• Amazon Seller Central: Monthly inventory storage fees
• Supply Chain Dive (reporting Amazon’s Seller Central notice): Amazon announces 2026 holiday fulfillment fees
• AMZ Prep: 2026–2027 Holiday Peak FBA Fulfillment Fees — Independent copy of the 2026 peak card; first-row figures for every tier match our derived table.
• Goat Consulting: 2026 Amazon FBA Fee Changes: Full Rate Card for Sellers — Full apparel, dangerous goods and returns processing tables; cross-checked row-by-row against My Amazon Guy where both publish.
• My Amazon Guy: Amazon FBA Fees 2026: Complete Cost Breakdown
• SellerGuards: Amazon Returns Processing Fee: Category Thresholds
• AMZ Prep: Amazon Low Inventory Level Fee 2026
• BQool: What are Amazon FBA Fees? 2026 Updates (full 2025/2026 tables)
• TechMachaw: Amazon Referral Fees and FBA Size Tiers: The 2026 Tables

International marketplaces: how each store is verified

Every store outside the US has its own engine, built from that store's Amazon pages and rate cards (read October 18, 2026). Each engine's automated tests reproduce the worked examples Amazon publishes for that store. Property tests check every store for impossible results: negative or missing fees, fees that fall as a parcel gets heavier (except where Amazon's own card does this, listed below), and the exact days peak rates, surcharges and launch incentives start and stop. The Europe rate card's main fulfilment table and storage rates are also kept as a fixture extracted from Amazon's PDF, and the data is compared with it on every build.

Where Amazon's own documents disagree or surprise

We reproduce the card as published and say so where it is odd:

• UK small oversize: the main Europe table prints +£0.25 per kg above 760 g; the peak page's non-peak column prints +£0.22. We use the main table.
• Amazon.ae watches: Amazon's referral example prints AED 1,150 for an AED 7,000 watch; its stated rule (15% to AED 5,000, 5% above) gives AED 850. We follow the rule.
• Amazon.nl: a small parcel up to 3.9 kg costs €5.90 on the card, more than a standard parcel up to 5.9 kg (€5.30).
• Amazon.es: the first small-oversize row (€5.68) is cheaper than the heavier standard-parcel rows (up to €7.85).
• Amazon.pl: the card prices Amazon.pl fulfilment in złoty at levels far below the euro stores, while it quotes storage for Poland in euros. We use the fulfilment figures as printed and convert storage at the ECB rate.
• Amazon.in: a 29 kg Heavy & Bulky unit costs less to fulfil than a 20 kg standard-size unit on the published schedule.
• Amazon.eg: a large envelope (EGP 26) costs more than a standard parcel up to 500 g (EGP 25.50).

Report a wrong number

If your Seller Central rate card or Fee Preview report disagrees with us, email [contact email, set at launch] with the size tier, weight, price and the fee Amazon shows. We correct the data, add a test for the case and log the change in the changelog.