A utility cart to carry at least one item having an item weight, said utility cart comprising: a cart structure adapted to carry the item, said cart structure having a cart structure weight and a cart mounting structure, and a weight sensor assembly, characterized in that said cart mounting structure has a plurality of spaced apart cart fastener openings extending into said cart mounting structure; and in that the utility cart further comprises a caster wheel assembly having a wheel mounting bracket with a bracket perimeter portion and an integrally formed bracket central area, said bracket perimeter portion having a plurality of bracket fastener openings in mated alignment with said cart fastener openings; the weight sensor assembly being located between said wheel mounting bracket and said cart mounting structure, said weight sensor assembly including a sensor plate with a sensor plate perimeter portion and an integral inwardly extending semi-flexible cantilevered support tab, said support tab having a tab neck, central focal area, tab surface and a strain gauge sensor, said strain gauge sensor being secured to said tab surface, said tab neck and focal area being surrounded by a flex accommodating opening, and said focal area being aligned directly over and in load supporting engagement with said central area of said wheel mounting bracket; a weight bearing crown formed on one of either said central area of said wheel mounting bracket and said central focal area of said support tab; a plurality of fasteners passing through said bracket fastener openings and into said cart fastener openings to firmly secure said caster wheel mounting bracket to said cart mounting structure; said fasteners leaving a non-load bearing gap between said bracket perimeter portion and said sensor plate perimeter portion; and, wherein said semi-flexible support tab flexes responsive to said cart weight and the item weight, and said strain gauge sensor produces strain gauge weight data sufficient to indicate one of either the item weight and said cart weight and the item weight. a cart structure adapted to carry the item, said cart structure having a cart structure weight and a cart mounting structure, and a weight sensor assembly, characterized in that said cart mounting structure has a plurality of spaced apart cart fastener openings extending into said cart mounting structure; and in that the utility cart further comprises a caster wheel assembly having a wheel mounting bracket with a bracket perimeter portion and an integrally formed bracket central area, said bracket perimeter portion having a plurality of bracket fastener openings in mated alignment with said cart fastener openings; the weight sensor assembly being located between said wheel mounting bracket and said cart mounting structure, said weight sensor assembly including a sensor plate with a sensor plate perimeter portion and an integral inwardly extending semi-flexible cantilevered support tab, said support tab having a tab neck, central focal area, tab surface and a strain gauge sensor, said strain gauge sensor being secured to said tab surface, said tab neck and focal area being surrounded by a flex accommodating opening, and said focal area being aligned directly over and in load supporting engagement with said central area of said wheel mounting bracket; a weight bearing crown formed on one of either said central area of said wheel mounting bracket and said central focal area of said support tab; a plurality of fasteners passing through said bracket fastener openings and into said cart fastener openings to firmly secure said caster wheel mounting bracket to said cart mounting structure; said fasteners leaving a non-load bearing gap between said bracket perimeter portion and said sensor plate perimeter portion; and, wherein said semi-flexible support tab flexes responsive to said cart weight and the item weight, and said strain gauge sensor produces strain gauge weight data sufficient to indicate one of either the item weight and said cart weight and the item weight.