When FedEx announced in early May that it would soon begin using both weight and size when determining how much to charge for delivering a parcel, we predicted that UPS would follow suit. Amazingly, Big Brown was able to hold off for an entire month before deciding it also needs to take a package’s dimensions into account for ground shipping.

Because this change would completely screw up a lot of companies’ holiday shipping budgets, UPS is delaying the change until Dec. 29.

According to UPS, the boom in e-commerce has resulted in a lot of things being shipped via UPS that were previously bought off store shelves. So rather than carrying densely packed boxes, UPS is now trucking around larger, lighter boxes, which is not as efficient in terms of space or fuel.

“The company believes that as a result of the dimensional weight pricing method, more shippers will seek to optimize their packaging practices,” UPS explains in a statement. “These efforts will reduce excess packaging materials and overall package sizes, leading to related reductions in fuel use, vehicle emissions and transportation costs.”

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