Understanding Shipping Surcharges: A Comprehensive Guide
This guide explains the carrier surcharges and adjustments you may see after purchasing a label on Palmstreet. These charges come directly from UPS, USPS or FedEx— not from Palmstreet — and occur when the carrier's audited shipment details don't match what was submitted at label creation.
How surcharges work
When you purchase a label, the price is based on the package details you enter at that moment. After your package enters the carrier network, the carrier uses automated scanning systems to re-verify weight, dimensions, address, and service type. If they find a mismatch, they issue an adjustment — an additional charge (or occasionally a credit) that appears in your account days or weeks after shipment.
What you'll see on a surcharge line item:
Carrier (UPS, USPS or FedEx)
Tracking number
Reason and description
Adjustment amount (positive = extra charge, negative = credit)
Understanding Dimensional (DIM) Weight — Read This First
This is the single most important concept for avoiding surcharges.
Carriers don't just charge by actual weight. They also calculate a dimensional weight based on your package's size, and charge whichever is larger.
Formula:
UPS:
(Length × Width × Height in inches) ÷ 225 = DIM weight (lbs)→ round up to the next whole numberFedEx:
(Length × Width × Height in inches) ÷ 139 = DIM weight (lbs)→ round up to the next whole numberUSPS:
(Length × Width × Height in inches) ÷ 166 = DIM weight (lbs)→ round up to the next whole number
Example: A 12 × 10 × 8 inch box with an actual weight of 2 lbs
DIM weight = (12 × 10 × 8) ÷ 139 = 6.9 lbs → 7 lbs
You will be billed for 7 lbs, not 2 lbs
Important note about Palmstreet labels:
When you purchase a label on Palmstreet, we automatically compare dimensional weight and actual weight to show the correct rate upfront.
However, if the package dimensions you enter are inaccurate, the carrier may remeasure the package during transit and apply a higher DIM/actual weight. The difference will be charged as a surcharge. This is why a surcharge may show a higher billed weight than what you originally entered — the carrier is charging based on dimensional weight, not actual weight.
1) Wrong Weight or Dimensions
What it means
The carrier's automated system measured your package and found the actual weight or dimensions different from what you declared at label creation. This is the most common surcharge type.
Common causes:
Measuring the product, not the packed box
Not accounting for box thickness — a box labeled "8×8×8" is measured from the outside including walls, so the carrier will scan it slightly larger
Packing materials (bubble wrap, packing peanuts) adding weight after the label was purchased
Entering weight in oz when lbs was intended, or vice versa
How to avoid:
Weigh and measure the fully packed, sealed box — not the product alone
Always round up to the next whole pound or half-inch
Double-check your unit: if a package feels like it weighs about 1 pound, enter
1in the lbs field, not the oz fieldIf your box is labeled with a size, add 0.25–0.5 inches per side to account for box wall thickness
2) UPS Large Package Surcharge
What it means
This surcharge applies to packages that exceed certain size or weight thresholds. It can be very expensive — averaging over $200 per case — because UPS automatically applies a minimum billable weight of 90 lbs regardless of your package's actual weight.
Triggers (any one of the following):
Length (longest side) exceeds 96 inches
Length + Girth exceeds 130 inches (Girth = 2 × width + 2 × height)
Volume exceeds 17,280 cubic inches (e.g., a 30 × 24 × 24 box = 17,280 cubic in)
Actual weight exceeds 110 lbs
Example: For a 25 × 20 × 20 inch box: Length + Girth = 25 + (2×20) + (2×20) = 105 inches — getting close. A 30 × 20 × 20 box = 130 inches — exactly at the threshold.
How to avoid:
Before buying a label, calculate:
Length + (2 × Width) + (2 × Height). Keep it under 130 inches.If you regularly ship large items (e.g., tall plants, large décor), measure your boxes in advance and note which ones are near the limit.
Note: Large Package Surcharge and Additional Handling are not both charged — UPS applies whichever is higher.
3) Additional Handling
What it means
Carriers charge this when a package requires special handling due to its size, weight, or packaging type.
Size triggers:
Longest side exceeds 48 inches
Second-longest side exceeds 30 inches
Length + Girth exceeds 105 inches
Weight trigger:
Actual weight exceeds 50 lbs
Packaging triggers (easy to overlook):
Package is not fully encased in corrugated cardboard — this includes wooden crates, metal containers, hard plastic cases
Package is in a soft-sided bag (poly mailer, bubble mailer) exceeding 18 × 14 × 6 inches (UPS) or 18 × 13 × 5 inches (FedEx)
Package is wrapped in shrink wrap or stretch wrap
Package has wheels, handles, or straps (e.g., a bag with a handle counts)
Package is cylindrical (tubes, buckets, barrels, drums) not encased in a box
Package contents protrude outside the box
How to avoid:
Always ship in a proper corrugated cardboard box
If using poly mailers or bubble mailers, stay within the size limits above
For irregular items (plants in pots, animals in ventilated carriers), use a standard box as the outer container
4) USPS Postage Correction
What it means
USPS runs every package through its Automated Package Verification (APV) system, which checks weight, dimensions, service type, and package type. If the paid postage doesn't match what USPS's system calculates, they issue a correction — either a charge or a credit.
The most common cause in our data is weight discrepancy, including the oz/lbs unit mismatch mentioned in Section 1. The second most common is dimension discrepancy.
Also watch for service class issues: USPS First Class Mail is only available for packages 16 oz (1 lb) or under. If you ship a package heavier than 16 oz using First Class, USPS will automatically upgrade it to Priority Mail or Ground Advantage and charge the difference. This happens silently — your package still gets delivered, but a surcharge appears later.
How to avoid:
Confirm your package is under 16 oz before selecting First Class, for anything over 1 lb, use Ground Advantage or Priority Mail
Please ensure measurements are taken according to the instructions in Section 1.
Make sure weight is entered in the correct unit (lbs vs oz)
5) UPS Shipping Charge Correction (DIM Correction)
What it means
UPS re-measures your package in their network and bills the corrected dimensional weight if it's higher than what you declared. This shows up as "Shipping Charge Correction" followed by the service name and the audited dimensions.
Common patterns we see:
Sellers declaring a box as 7×7×7 when the actual scanned size is 8×8×8 or larger
Long, narrow packages (e.g., 25×7×7) where the length was underreported
Plant shippers using non-standard box sizes and estimating rather than measuring
How to avoid:
Measure after packing, at the widest points including any bulges or tape
Always round up to the next whole inch on each dimension; UPS is strict with measurements, so even if your package is 5.05 inches wide, please round it up to 6 inches to avoid potential surcharges.
For elongated packages (tubes, tall plant boxes), pay extra attention to length accuracy
6) Demand Surcharge (UPS)
What it means
During periods of high network demand — primarily holiday season (eg. October through January) — UPS applies temporary surcharges to certain shipments. These are applied by UPS based on dates, service types, and destination zones, and are outside your control.
Palmstreet will notify you when demand surcharges are in effect. Outside of peak season windows, you will not see this charge.
How to reduce impact:
Ship earlier in the day or earlier in the week during peak season when possible
This surcharge cannot be avoided entirely during peak periods, but understanding it in advance helps you factor it into your pricing
7) Zone Adjustment
What it means
The carrier re-determined the shipping zone for your package based on the actual origin/destination routing. A zone change can alter the base shipping cost.
Zone adjustments can happen even when you entered the correct ZIP codes. This is because the carrier sometimes routes packages through different facilities than expected — the zone is determined by where your package actually enters and exits the network, not just the origin and destination ZIPs. This is a carrier routing decision and are outside your control.
8) Label Misuse
What it means
Each label is valid for one specific shipment, one time only. Carriers flag misuse and charge accordingly.
Duplicate Use:
Using the same label on more than one package. The carrier will charge the full shipping cost for each additional use. There is also a risk that the second package may be discarded or not delivered.
Unauthorized Use:
Using a voided, canceled, or previously refunded label. This includes reprinting a label for a different package or using a label after shipment details have changed. This carries a higher risk that the package may be rejected or discarded by the carrier.
How to avoid:
Never reprint a label for a second package
If a shipment falls through or address changes, void the label and create a new one
If reshipping a lost order, always purchase a new label
Quick Checklist Before Buying a Label
Note on package type (USPS): If you are using a USPS-supplied Flat Rate or Regional Rate box, make sure you select the matching package type at label creation. Using a Flat Rate box with the wrong service type will result in a postage correction. When in doubt, use your own box and select Ground Advantage — it works for all standard packages up to 70 lbs.
Keep your records. Carrier adjustments can appear 2–8+ weeks after your ship date. If you need to dispute a charge, having the original label details (weight, dimensions, service, destination) and photos of the packed box will significantly help your case. If you believe a surcharge was applied in error, contact Palmstreet support with the tracking number and we will review it with the carrier.
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