US FDA Food Labeling Regulations (21 CFR Part 101) 101.105: Net quantity of contents: on the PDP in the lower 30 percent, in weight, measure or count with metric and US customary units, in the minimum type sizes by PDP area, free from packaging material and with the reasonable variation and 'jumbo' prohibitions (101.105)

The net quantity of contents must appear on the PDP as a distinct item in the bottom 30 percent of the panel, on lines running parallel to the base, in weight for solids, fluid measure for liquids, or numerical count where appropriate, in both US customary and metric (SI) units, in the largest whole unit with the remainder in common fractions or decimals, in type of at least one-sixteenth inch for PDP areas up to 5 square inches, one-eighth inch for 5 to 25 square inches, three-sixteenths inch for 25 to 100, one-quarter inch for 100 to 400, and one-half inch above 400, separated from other printed matter by the required clear space, and exclusive of wrappers and packaging materials (including those on multi-unit packages). Reasonable variations from unavoidable deviations in good manufacturing practice are permitted, but variations that are unreasonably large or that result from improper filling are misbranding; qualifying terms such as 'jumbo quart' or 'full gallon' may not be used, and supplemental statements may not be false or misleading.