Standard shipping rates assume a rectangular box. When your package is cylindrical, tube-shaped, poly-bagged, or otherwise irregular, both USPS and UPS have specific rules that change how your dimensions are measured — and in some cases, add surcharges to your shipment.
This article covers how each carrier defines an irregular package, how dimensional weight and volume are calculated differently for non-rectangular shapes, and what additional fees may apply.
Shipping an irregular package without understanding carrier rules can result in unexpected charges after the label is created. Both USPS and UPS may recalculate your billable weight, apply surcharges, or route your package differently based on its shape. Knowing these rules upfront helps you accurately quote shipping costs and avoid surprises.
USPS defines an irregular parcel as any package that is not shaped like a rectangular solid — meaning it is not a standard box with six flat, rectangular sides.
Dimensional weight (DIM weight) for non-rectangular packages
For standard rectangular boxes, USPS calculates DIM weight as:
Length × Width × Height ÷ DIM divisor
For non-rectangular or cylindrical packages, USPS applies a shape adjustment factor of 0.785 to account for the fact that the package doesn't fill its bounding box:
Length × Width × Height × 0.785 ÷ DIM divisor
This factor reflects the approximate volume of a cylinder relative to the rectangular space it occupies. The result is a lower calculated DIM weight compared to a rectangular box of the same outer dimensions — which can work in your favor for round or tube-shaped items.
Nonmachinable surcharge
USPS may also apply a nonmachinable surcharge to parcels that cannot be processed on automated equipment. While shape alone does not always trigger this fee, packages that are rigid, oddly weighted, or have protrusions may be classified as nonmachinable and assessed an additional charge.
Measurement guidance
For irregular shapes, USPS measures the bounding box — the smallest rectangular box that fully contains the item — to determine length, width, and height. The 0.785 factor is then applied to the volume calculated from those outer dimensions.
UPS uses the term Additional Handling to identify packages that require special sortation or processing outside their normal automated systems. An Additional Handling charge is assessed per package and applies to both domestic and international shipments.
Packages that trigger Additional Handling
UPS will assess an Additional Handling charge for any of the following:
Weight
Domestic: actual weight over 50 lbs
International: actual weight over 55 lbs
Any shipment where the average weight per package exceeds these thresholds and individual package weights are not specified
Size
Length + Girth [(2 × width) + (2 × height)] exceeds 105 inches
Longest side (length) exceeds 48 inches
Second-longest side (width) exceeds 30 inches
Packaging / Shape
Any article not fully encased in corrugated cardboard, including tires
Outer container made of canvas, leather, metal, wood, hard plastic, soft plastic (e.g., plastic bag), or expanded polystyrene foam (e.g., Styrofoam)
Soft-sided packs (poly bags, bubble mailers) exceeding 18 inches on the longest side, 14 inches on the second-longest side, or 6 inches in height
Packages covered in shrink wrap or stretch wrap
Packages bound with metal, plastic, or cloth banding, or that have wheels, casters, handles, or straps
Cylindrical-like items, including barrels, buckets, cans, drums, mailing tubes, or pails
Packages 1 inch or less in height (routed through UPS's irregular package sortation process)
Any package requiring special handling as determined by UPS
Minimum billable weight
For packages flagged due to size (Length + Girth, Length, or Width), UPS applies a minimum billable weight of 40 lbs — unless the package qualifies for UPS Ground with Freight Pricing. Weight- and packaging-triggered surcharges do not carry this minimum.
Multiple criteria — one charge
If a package meets more than one Additional Handling criterion, only one charge is applied. UPS prioritizes in this order: Weight → Length + Girth → Length → Width → Packaging.
Additional Handling vs. Large Package Surcharge
If UPS applies a Large Package Surcharge to a shipment, the Additional Handling charge is not assessed on top of it — only one applies.
When entering package dimensions in Deliveri, use the bounding box measurements (the outer dimensions of the space the package occupies) regardless of shape.
For UPS shipments, Deliveri passes your entered dimensions and weight to UPS. If your package meets any Additional Handling threshold, the surcharge will be shown in your rate breakdown before you complete your purchase.
Additional Handling and Large Package Surcharges from UPS are billed separately and will appear on your Deliveri billing statement after carrier reconciliation.
If you're unsure whether your package qualifies as irregular or non-rectangular, contact Deliveri support before purchasing the label.
USPS doesn't have a separate "irregular package" surcharge, but it does calculate DIM weight differently — using a 0.785 factor — which lowers the dimensional weight for non-rectangular shapes. A nonmachinable surcharge may apply in some cases depending on the parcel's characteristics.
The Additional Handling charge applies to both domestic and international UPS services, per package. The only exception is that it is not assessed when a Large Package Surcharge is already applied.
Yes — Deliveri displays the UPS Additional Handling charge in your rate breakdown before you complete your purchase, so you'll know the full cost before buying the label.
Yes — if a poly bag or bubble mailer exceeds 18 inches on the longest side, 14 inches on the second-longest side, or 6 inches in height, UPS will assess an Additional Handling charge.
Always enter the bounding box dimensions — the length, width, and height of the smallest rectangular box that would fully contain the item. USPS handles any volume adjustment for irregular shapes on their end automatically.
Only the Large Package Surcharge applies. UPS does not charge both simultaneously.
Not sure how your irregular package will be rated or whether it qualifies for Additional Handling? Reach out to the Deliveri team and we'll help you figure it out before you buy the label. Contact Deliveri support through live chat or email help@ondeliveri.com.
Related articles:
Understanding UPS Surcharges and Fees
How Dimensional Weight Is Calculated on Deliveri
USPS Nonmachinable Parcels and When They Apply
