FBA size tiers are measurement categories Amazon assigns to a packaged unit from its unit weight, dimensions, and dimensional weight. Since January 15, 2026, the US store has eight: Small standard-size, Large standard-size, Small Bulky, Large Bulky, and four Extra-Large bands. The tier sets your fulfillment fee, storage rate, removal and disposal fees, and inbound placement fees — which is why a tenth of an inch can move a product between two fee schedules.
Every figure below comes from Amazon’s Seller Central help articles and applies to selling in the United States (amazon.com) — the size tier article carries the banner “This article applies to selling in: United States.” The UK and EU stores publish their own tier tables in metric units; do not reuse these inches, pounds, or dollar rates there. Data checked 2026-07-28.
The 2026 US FBA size tier table
These definitions took effect January 15, 2026, replacing the 2024 definitions that ended January 14, 2026.
| Product size tier | Shipping weight | Longest side | Median side | Shortest side | Length + girth |
|---|---|---|---|---|---|
| Small standard-size | Up to 16 oz | Up to 15 in | Up to 12 in | Up to 0.75 in | N/A |
| Large standard-size | Up to 20 lb | Up to 18 in | Up to 14 in | Up to 8 in | N/A |
| Small Bulky | Up to 50 lb | Up to 37 in | Up to 28 in | Up to 20 in | Up to 130 in |
| Large Bulky | Up to 50 lb | Up to 59 in | Up to 33 in | Up to 33 in | Up to 130 in |
| Extra-Large 0 to 50 lb | Up to 50 lb | — | — | — | — |
| Extra-Large 50+ to 70 lb | 50+ to 70 lb | — | — | — | — |
| Extra-Large 70+ to 150 lb | 70+ to 150 lb | — | — | — | — |
| Extra-Large 150+ lb | Over 150 lb | — | — | — | — |
Source: Product size tiers, Amazon Seller Central (US), data checked 2026-07-28.
Amazon groups the first two tiers as standard size and the other six — Small Bulky, Large Bulky, and the four Extra-Large bands — as Oversize. A report calling a listing “oversize” therefore tells you it is not standard, but not which of the six tiers it is in.
The Extra-Large bands have no dimension ceiling: a unit lands there by exceeding 59 inches on the longest side, 33 inches on the median or shortest side, or 130 inches length plus girth — or by exceeding 50 lb shipping weight. Weight then picks the band. An Extra-Large unit up to 150 lb exceeding 96 inches on the longest side or 130 inches length plus girth is additionally Overmax, which adds a surcharge.
How Amazon decides which tier you are in
Unit weight is the physical weight of the packaged individual unit.
Dimensional weight is unit volume (length × width × height in inches) divided by 139. For Small Bulky, Large Bulky, and Extra-Large items, Amazon assumes a minimum width and height of 2 inches when computing it.
Shipping weight is the figure that drives fees, and it is the greater of unit weight and dimensional weight — with two exceptions. Small standard-size and Extra-Large 150+ lb use unit weight only.
Girth = 2 × (median side + shortest side), where the median side is the dimension that is neither longest nor shortest. So “length plus girth” is longest side + 2 × (median + shortest), not the perimeter of one face.
Amazon’s two published examples show how tight the standard-size boundary is:
| Product | Dimensions | Unit weight | Tier |
|---|---|---|---|
| Mobile device case | 13.8 × 9 × 0.7 in | 2.88 oz | Small standard size |
| T-shirt | 8.5 × 4.8 × 1 in | 6.08 oz | Large standard size |
The t-shirt is shorter and narrower than the phone case, yet lands a tier higher: its shortest side is 1 inch against a 0.75 inch cap, and that 0.25 inch decides it. Weight is not the reason — the t-shirt’s 6.08 oz beats the case’s 2.88 oz, but both sit far under the 16 oz Small standard-size cap. Compression is a packaging decision, not a listing edit — see our Amazon FBA prep software roundup.
What changed on January 15, 2026: the Small Bulky split
Before that date, everything from just above Large standard-size up to 59 inches and 50 lb sat in a single Large Bulky tier on one rate card. Amazon split it in two and gave the smaller half cheaper rates.
| 2024 definitions (ended Jan 14, 2026) | 2026 definitions (from Jan 15, 2026) | |
|---|---|---|
| Tiers between standard and Extra-Large | Large Bulky only | Small Bulky and Large Bulky |
| Small Bulky limits | — | 50 lb / 37 in / 28 in / 20 in / 130 in L+girth |
| Large Bulky limits | 50 lb / 59 in / 33 in / 33 in / 130 in L+girth | Unchanged |
Because Small Bulky was carved out of Large Bulky rather than out of standard size, the cheaper rates applied automatically — no re-listing, no enrollment. Large Bulky limits are unchanged, so a unit above 37 inches keeps the Large Bulky rate card.
Fee impact: what each tier costs
US non-peak rates for non-apparel, non-dangerous-goods items, January 15 to October 14, 2026, by price band. The 3.5% surcharge described below is not included.
| Size tier | Shipping weight | Under $10 | $10–$50 | Over $50 | Increment above base |
|---|---|---|---|---|---|
| Small standard | 2 oz or less | $2.43 | $3.32 | $3.58 | — |
| Small standard | 14+ to 16 oz | $2.95 | $3.96 | $4.22 | — |
| Large standard | 4 oz or less | $2.91 | $3.73 | $3.99 | — |
| Large standard | 3+ to 20 lb | $6.15 | $6.97 | $7.23 | $0.08 per 4 oz above 3 lb |
| Small Bulky | 0 to 50 lb | $6.78 | $7.55 | $7.55 | $0.38 per lb above 1 lb |
| Large Bulky | 0 to 50 lb | $8.58 | $9.35 | $9.35 | $0.38 per lb above 1 lb |
| Extra-Large | 0 to 50 lb | $25.56 | $26.33 | $26.33 | $0.38 per lb above 1 lb |
| Extra-Large | 50+ to 70 lb | $36.55 | $37.32 | $37.32 | $0.75 per lb above 51 lb |
| Extra-Large | 70+ to 150 lb | $50.55 | $51.32 | $51.32 | $0.75 per lb above 71 lb |
| Extra-Large | 150+ lb | $194.18 | $194.95 | $194.95 | $0.19 per lb above 151 lb |
Source: 2026 US FBA fulfillment fee changes, Amazon Seller Central (US), data checked 2026-07-28. Apparel and dangerous goods have separate rate cards there.
The Small Bulky base rate is $1.80 below Large Bulky. In the $10–$50 band, Small Bulky starts at $7.55 against $9.35. Both add the same $0.38 per pound, so the gap stays flat at $1.80 at any weight.
Price bands do not break ties in the seller’s favour. Items priced at exactly $10 and exactly $50 both fall in the $10–$50 band. Products under $10 automatically get Low-Price FBA rates, which Amazon says average $0.86 per unit below standard rates.
Peak rates replace these from October 15, 2026 to January 14, 2027. Small Bulky rises to an $8.59 base in the $10–$50 band and Large Bulky to $10.39.
The fees your tier drives beyond fulfillment
Amazon lists seven fees that use the size tier attribute: FBA fulfillment fees, monthly inventory storage fees, the aged inventory surcharge, removal order fees, disposal order fees, Multi-Channel Fulfillment fees, and inbound placement service fees.
Monthly storage. For non-dangerous goods off-peak (January–September), the base rate is $0.78 per cubic foot for standard-size and $0.56 for oversize; peak (October–December) base rates are $2.40 and $1.40. A storage utilization surcharge is added on top, reaching $1.88 per cubic foot for standard-size at 52+ weeks. Source: Monthly inventory storage fees, Amazon Seller Central (US), data checked 2026-07-28.
Packaging fee for bulky items. From January 15, 2026, Small Bulky and Large Bulky units not enrolled in Ships in Product Packaging (SIPP) pay a packaging fee when they need Amazon-supplied packaging. Amazon states it averages $2.07 per unit, scaled by dimensional weight from $1.51 (0–5 lb) to $4.04 (45 lb or more).
SIPP discount changes. Standard-size SIPP-certified units keep a non-apparel discount of $0.04 to $0.23 per unit. The flat $1.32 Large Bulky SIPP discount was deprecated on January 15, 2026, replaced by the lower bulky base rates.
Overmax handling fee. From January 15, 2026, Overmax units pay an extra $17 (0–50 lb), $21 (50+ to 70 lb), or $25 (70+ to 150 lb) on top of the fulfillment fee. Source: Overmax Handling Fee, Amazon Seller Central (US), data checked 2026-07-28.
Fuel and logistics surcharge. From April 17, 2026, a 3.5% surcharge applies to FBA fulfillment fees in the US and Canada, including peak fees. No rate card figure above includes it.
The wider 2026 changes are covered in our Amazon 2026 fee changes guide; how these stack against referral fees and COGS is worked through in FBA fees and profit.
Worked examples from Amazon’s own rate card
Amazon publishes four bulky examples with its own arithmetic. Totals include SIPP discounts and packaging fees where they apply.
| Product | Dimensions | Shipping weight | 2025 total | 2026 total |
|---|---|---|---|---|
| Vent cover filter (Small Bulky, SIPP) | 18 × 17.75 × 2.75 in | 6+ to 7 lb | $10.31 | $9.57 |
| Baby cot (Small Bulky, non-SIPP) | 24 × 7.5 × 6 in | 7+ to 8 lb | $12.27 | $12.18 |
| Shoe storage bench (Large Bulky, SIPP) | 47.5 × 17.25 × 4.38 in | 25+ to 26 lb | $17.71 | $18.77 |
| Book shelf (Large Bulky, non-SIPP) | 37.58 × 12.27 × 5.74 in | 30+ to 40 lb | $20.74 | $23.08 |
Source: Ships in Product Packaging (SIPP) FBA fulfillment fee, Amazon Seller Central (US), data checked 2026-07-28. 2025 figures are the October 15, 2025 to January 14, 2026 rates.
The book shelf is the case worth studying: its fulfillment fee fell from $20.74 to $20.48, but the $2.60 packaging fee on a non-SIPP bulky unit turned that into a $2.34 increase. The baby cot shows the same mechanism smaller — a $2.06 fulfillment saving from the split, mostly eaten by a $1.97 packaging fee. SIPP enrollment status now decides whether 2026 was a discount or a rise.
Where size tier assignments go wrong
Dimensions are measured on the packaged unit, not the product. Loose or deformable packaging inflates them, and Amazon uses the greater of unit and dimensional weight for every tier except Small standard and Extra-Large 150+ lb.
Amazon re-measures in the fulfillment center. Catalog dimensions are an input, not the final word, and a wrong measurement charges the wrong tier on every unit shipped until corrected. The product-size-tier field in the Fee Preview report shows Amazon’s current view of each FNSKU, and the Product size tiers page cited above routes wrongly measured units to the FBA Remeasurement and Reimbursement Tool to check eligibility.
Overcharges are recoverable but not automatic. Mis-tiered units surface when a fee preview is reconciled against what was charged. ReimburseOps is one self-serve option: it audits an uploaded Seller Central reimbursement CSV against sourcing costs, has a free tier showing partial results, and charges a flat $19/month for Pro with no commission on recoveries — it does not connect to Seller Central or file claims for you. Managed alternatives that do file for you are compared in our FBA reimbursement services roundup.
Calculators lag rate card changes. Before trusting a 2026 estimate for a bulky product, confirm the tool carries the split rate card — our review of free FBA fee calculators covers which ones track official changes.
Frequently Asked Questions
What are the FBA size tiers in 2026?
Eight in the US store: Small standard-size, Large standard-size, Small Bulky, Large Bulky, and Extra-Large in four weight bands (0–50 lb, 50+–70 lb, 70+–150 lb, 150+ lb). Small Bulky was added on January 15, 2026.
What is the Small Bulky size tier?
Small Bulky covers packaged units up to 50 lb with a longest side up to 37 inches, median side up to 28 inches, shortest side up to 20 inches, and length plus girth up to 130 inches. It took effect January 15, 2026 and carries a lower fulfillment rate than Large Bulky.
How do I find my product’s size tier?
Download the Fee Preview report in Seller Central, find the product by FNSKU, and read the product-size-tier field. For products not yet in FBA, apply the measurement rules above to your packaged unit.
Does dimensional weight always apply?
No. Small standard-size and Extra-Large 150+ lb use unit weight only. All other tiers use the greater of unit weight and dimensional weight.
Do these size tiers apply outside the United States?
No. Every limit and rate here comes from Amazon’s US help pages, which state they apply to selling in the United States. Other marketplaces publish their own tier tables and rate cards.
Bottom line
Size tier is an assignment, not a setting: it falls out of the packaged unit’s dimensions and weight, then propagates into seven fee lines. The 2026 change created one real discount (Small Bulky, $1.80 below Large Bulky at base) and one real cost (the $2.07 average packaging fee on bulky units outside SIPP). Which side a bulky product sits on decides whether this year helped or hurt it.