Plain answers to the problems shippers run into, each with the calculator that checks your own numbers.
Carriers re-measure packages in transit. A one-inch difference on one side can add a pound to the bill, and the difference lands on your account.
Shipping platforms estimate before the carrier measures. Learn where their divisors and rounding differ from the carrier's.
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Dimensional weight calculator
The widest point, bulges, outside versus printed box size, and why every side rounds up to a whole inch.
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Dimensional weight calculator
Packaging changes that lower the billable weight, and how to see the effect before you ship.
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Box size calculator
Measure, weigh and document so the class on your bill of lading matches the one the carrier assigns.
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Freight class calculator
NMFC, density, and why the scale changed in 2025, with the dated change log.
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Freight class calculator