With direct-to-consumers shipments on the rise, recent changes in the cost structure for small parcel deliveries are squeezing profits for product manufacturers and fulfillment houses. But there could be relief from a surprising source: the United States Postal Service.

Called dimensional weight or dim weight, this new pricing structure for ground shipments was implemented Jan. 1, 2015, by the three major shippers—FedEx, UPS and DHL. Shipping cost is now determined by the volume of a box rather than its weight for all sizes. Previously, boxes less than three cubic feet were exempt from dim-weight pricing.

You can learn more about the dim weight issue from this free white paper from Sealed Air, which also explains how shippers can minimize the financial impacts by optimizing their cases.

Steve Placek, a representative of the United States Postal Service, is quick to point out that small-parcel shippers have a no-dim-weight option that they might not know about. A huge sign in the USPS booth at the recent WestPack show declared “You don’t be a dim weight”—and stopped me in my tracks.

Placek tells me that the USPS has seen a significant jump in business so far this month, after many companies got an inflated bill from their January shipments. Advantages of shipping via USPS include:

• No surcharges for residential/rural residential delivery;

• No fuel surcharge;

• No contract;

• Access to an easy-to-use free online program—Click-n-Ship—for label creation; and

• No dim-weight pricing for boxes smaller than 1,728 cubic inches (about 1 cubic foot).

For boxes 1,728 inches or bigger, it gets a bit complicated to figure out which ones are subject to dim weight and which ones are not. Placek explains that there are 9 zones, depending on how far your shipment has to go (9 is the farthest). Whenever the zone is 5 or higher, USPS ships all boxes by air, not ground. In comparison, Placek says, the big three shippers send “ground” shipments by ground regardless of how far the case goes.

But because the USPS does not have its own air fleet, it has to pay for space on a plane when it uses this method of transportation. Because of this, the USPS will charge dim-weight pricing for parcels that are 1,728 cubic inches or larger that are shipping to zones 5 through 9.

Shippers still using FedEx, UPS or DHL can get some help automating their dim weight shipments. On display at WestPack, the CubiScan 200-TS integrated in-motion dimensioning and weighing system from QMI Services measures and weighs parcels on-the-fly using infrared light-technology.