What is the concept applies to UPS using dim calculator? The same concept applies to UPS. UPS states that for packages with a large size-to-weight ratio, dimensional (DIM) weight may be used to calculate shipping costs. When dimensions are entered into the UPS shipping system, the DIM weight may be displayed as the billable weight if applicable. Therefore, a business can first check using a calculator: Current Box 20 × 16 × 12 ↓ DIM = 28 lb Then: Optimized Box 14 × 12 × 8 ↓ DIM = 10 lb The business then calculates the actual savings based on its UPS, FedEx, or USPS rates. There are benefits with USPS as well. USPS also applies dimensional-weight pricing for large, lightweight packages within certain parcel classes. USPS itself notes that a package's shape, weight, and size can affect the price.