Interstate household goods are priced by weight, and the weight on the invoice is supposed to come from a scale. Constructive weight is the exception word: a figure produced by arithmetic when there is no scale ticket for the portion of the load in question.
Actual weight versus constructive weight
Actual weight is what a certified scale reads. Under 375.509, the mover subtracts the empty truck, called the tare, from the loaded truck, called the gross, and the net is your shipment. Constructive weight is the estimate of that figure when a scale reading is unavailable or the tariff directs a calculation instead.
Where the rules mention it
Section 375.707(b) uses it in the lost-or-destroyed shipment rule: the mover must determine, at its own expense, the proportion of the shipment, based on actual or constructive weight, that was not lost or destroyed. That is how freight charges for a partly delivered load are prorated.
Section 375.401(e) covers the reverse case, an estimate based on volume. When a mover gives you a volume-based estimate that will later be converted to a weight-based rate, it must give you the conversion formula in writing, and it must state that the final charges follow actual weight and services, subject to the 110 percent rule at delivery.
What it means for your invoice
- On a non-binding estimate, final charges use the weight from the weight ticket, not the cubic feet written during the survey
- A formula that converts cubic feet to pounds has to be explained in writing before you sign
- In a partial loss, a calculated weight sets the portion of freight charges refunded
- A binding estimate fixes the price for the quantities listed, so the weight conversion matters less once it is signed
How to check it
Ask the estimator how the volume on your estimate becomes pounds, and keep the written formula with your papers. At delivery, compare the weight ticket with the estimate. If you disagree with the billing weight, you can demand a reweigh before unloading starts, as explained under reweigh. The numbers on a weight ticket are covered in weight ticket.
Why local movers use volume at the survey
A survey counts furniture and cartons, and cubic feet is the unit that comes out of counting. The weight conversion is the mover's bridge from that count to a priced estimate. A careful in-home look at the garage, closets and attic is what makes the bridge short.