Shortest-Side & Size-Tier Cliff Checker
Exceeding a tier’s shortest-side limit by a few millimeters—such as US FBA’s 0.75 in cutoff, UK/EU’s 2.5 cm / 6 cm envelope limit, or Royal Mail’s 16 cm Small Parcel depth—triggers steep fee jumps. Audit all three sorted edges below.
1. Marketplace & Packaged Item Specs
2. Size-Tier & Edge Cliff Audit
Right on a tier boundary? Test slimmer poly mailers or custom-die boxes to drop a tier.
Explore Slim Packaging →Size-Tier Threshold Breakdown
| Tier Name | Max Longest | Max Median | Max Shortest | Max Weight | Volumetric / DIM Rule |
|---|
Critical Packaging Cliffs Across US, UK/EU & Australian Networks
1. Envelope & Small Standard Thickness Walls (0.75 in / 2.5 cm)
In Amazon US FBA (15" × 12" × 0.75"), Amazon UK/EU (33 × 23 × 2.5 cm), and Amazon Australia (34 × 24 × 2.5 cm), items inside the Envelope / Small Standard tier are billed strictly on actual scale weight—volumetric weight is completely waived. Adding bulky bubble wrap that pushes thickness over 0.75" or 2.5 cm immediately activates dimensional weight billing.
2. Royal Mail 16 cm Depth & US Bulky 2-Inch Minimum Floors
In the UK, Royal Mail Small Parcels cap depth at 16 cm (45 × 35 × 16 cm); a 17 cm box jumps to Medium Parcel pricing. Meanwhile, in US FBA Bulky tiers, any edge thinner than 2 inches is rounded up to 2 inches in the DIM weight formula.