49 CFR § 375.507
Must I determine the weight of a shipment?
November 18, 2020
(a) When you transport household goods on a non-binding estimate dependent upon the shipment weight, you must determine the weight of each shipment transported before the assessment of any charges.
(b) You must weigh the shipment upon a certified scale.
(c) You must provide a written explanation of volume to weight conversions, when you provide an estimate by volume and convert the volume to weight.