Reselling News: USPS Changes How It Measures Your Boxes, and eBay Cushions the Rate Hike

The biggest reselling story this week is not a fee percentage. It is how USPS now measures your packages. Two changes took effect July 12, and one of them can raise your shipping cost on a box that weighs the same as it did last week.

USPS changed the math on package size

Starting July 12, USPS lowered its dimensional weight divisor from 166 to 139, and it now rounds every fractional package dimension up to the next whole inch when calculating postage. Both changes are confirmed in the USPS July 2026 price change announcement and broken down clearly by Pirate Ship.

Here is what that means in plain terms. Dimensional weight is a billed weight based on how much space a box takes up, and it kicks in on larger packages. A lower divisor produces a higher dimensional weight from the same box, so a light item in a big box now costs more to ship. On top of that, a box that measures 10.2 inches is now billed as 11 inches, because USPS rounds up instead of using the real number.

What to do: measure your boxes before you build them into a cost. Downsize your packaging where you safely can, because empty space is more expensive than it was a week ago. If you sell bulky-but-light items like pillows, lampshades, or foam, this is the change that touches you most. This is exactly the kind of number that quietly eats a flip's margin if you are not watching it.

eBay is cushioning the Ground Advantage hike

The same July 12 update eliminated ounce-based rate tiers on published USPS Ground Advantage commercial prices, an average increase of about 11.8 percent for sellers on those published rates, per EcommerceBytes.

The good news for eBay sellers: on July 8, eBay told sellers that eBay Labels would keep the same tiered Ground Advantage weight pricing for continental U.S. packages under one pound, at 4 oz, 8 oz, and 12 oz, with no rate increase at this time. That is eBay using its negotiated carrier rates to absorb a change that hits sellers buying labels elsewhere.

There are two catches. For non-continental destinations and some rural zip codes, USPS now charges the same rate within each zone regardless of ounces, so lightweight shipments to Alaska, Hawaii, Puerto Rico, military addresses, and rural areas can jump a few dollars. And eBay Standard Envelope rates did tick up on July 12, to $0.78 for 1 oz, $1.07 for 2 oz, and $1.36 for 3 oz.

What to do: if you sell lightweight items and you were shipping outside eBay Labels to save a few cents, run the numbers again this week. The tiered pricing eBay preserved may now be your cheapest option for small parcels under a pound.

The takeaway

Shipping is the line item resellers underestimate most, and this month USPS moved it in a way that rewards sellers who measure and punishes sellers who guess. Right-size your boxes, recheck your cheapest label path, and treat postage as a number you manage, not a number that happens to you. We break down how shipping and fees flow through to real profit on every flip inside The Income Lab.