On one pair of services it refuses the parcel. On another it just changes the price. That is the whole source of the confusion.
The ceilings, service by service
| Service | Max weight | Max length plus girth | Oversized pricing starts at |
|---|---|---|---|
| Priority Mail Express | 70 lb | 108 in | not applicable at this ceiling |
| Priority Mail | 70 lb | 108 in | not applicable at this ceiling |
| USPS Ground Advantage | 70 lb | 130 in | above 108 in |
| Media Mail | 70 lb | 108 in | not stated in the limits we captured |
| Library Mail | 70 lb | 108 in | not stated in the limits we captured |
| Parcel Select | 70 lb | 130 in | above 108 in |
Read the last two columns together and the arguments online resolve themselves. Both figures are real, and each is the answer to a different question.
Why sources disagree on 108 against 130
- On Priority Mail and Priority Mail Express, 108 inches is a refusal line. Past it, those services do not carry the parcel at all, so any page describing 108 as the USPS maximum is talking about these two.
- On Ground Advantage and Parcel Select, 108 inches is a pricing line. Past it the parcel is still accepted and moves into oversized pricing, with the actual refusal line sitting at 130 inches. Any page quoting 130 as the maximum is talking about these.
- The 70 lb weight ceiling has no such split. It applies across every service in the table, with no oversized band above it. At 71 lb the parcel simply is not postal any more.
The practical rule for anything bulky: work out length plus girth first, and treat 108 inches as the number that matters. Below it every service is open to you. Between 108 and 130 you have fewer services and a different price. Above 130, USPS is out of the conversation entirely.
Real cartons against the ceiling
Ordinary boxes sit a long way inside these limits, which is worth seeing before anyone panics about girth arithmetic. Here are four we quoted, measured against both lines.
| Carton | Length plus girth | Under 108 in | Under 130 in | Cheapest quote that day |
|---|---|---|---|---|
| 12 x 10 x 6 in, 5 lb | 44 in | yes | yes | $13.52 |
| 16 x 14 x 10 in, 16 lb | 64 in | yes | yes | $20.50 |
| 20 x 16 x 12 in, 32 lb | 76 in | yes | yes | $32.09 |
| 24 x 18 x 14 in, 50 lb | 88 in | yes | yes | $45.01 |
The heaviest of those is the interesting one. A 24 x 18 x 14 in carton loaded to 50 lb measures 88 inches of length plus girth and 20 lb under the weight ceiling, so it is comfortably inside every USPS limit on the page. Its quote came back with five rates on 2026-07-28 and not one of them was USPS; the cheapest was UPS Ground at $45.01 with a 2-3 business day window. Being inside a limit and being priced well are different things, and the only way to tell them apart is to look at the rates.
Measure the carton, not the item
Limits are written against the outside of the package as it will travel, tape and all. A frame that measures 100 inches diagonally is irrelevant; the box around it is what gets measured on the belt.
Weight is the simpler ceiling
Seventy pounds, every service, no exceptions and no oversized band. If you are near it, weigh the packed box rather than adding up the contents, because packaging on a large carton can run several pounds on its own.
Above the ceiling is not the end
Other carriers take parcels well past the postal limits, up to 150 lb and 165 inches of length and girth, and past that a shipment moves to freight. SMKlog sells parcel labels only and does not arrange pallet or freight shipments.
Size limit questions
What is the maximum package size for USPS?
USPS caps almost every service at 108 inches of length plus girth — including Media Mail, Library Mail, Priority Mail and Priority Mail Express. The 130-inch ceiling applies only to USPS Ground Advantage at commercial prices (the rate an online label uses), Parcel Select Destination Entry and USPS Connect Local (DMM 201, read 2026-08-22). Every one of those services caps weight at 70 lb.
Is the USPS limit 108 inches or 130 inches?
Both, for different services and different reasons. On Priority Mail and Priority Mail Express, 108 inches is where the service stops accepting the parcel. On Ground Advantage and Parcel Select, 108 inches is where oversized pricing begins and 130 inches is the refusal line.
What is the heaviest package USPS will ship?
Seventy pounds, on every service listed in Notice 123. There is no oversized band above that figure, so a 71 lb parcel needs a different carrier rather than a surcharge.
How do I work out length plus girth?
Take the longest side as the length, then add twice the width and twice the height. A 24 x 18 x 14 in carton comes to 88 inches, which sits well inside both the 108 and the 130 inch lines.