Manufacturers publish loader lift capacity at the pivot pin, a figure measured with no bucket or attachment fitted and with the load hanging at the pin itself. Nobody carries a load there. This calculator uses lift capacity 24 inches forward of the pin, the SAE J1234 point that corresponds to a load sitting in a bucket or on forks, and it takes that figure from the manufacturer document wherever one publishes it. Where only a pin rating exists, the page states that the working figure is derived from it and shows the derate applied. Enter a tractor and the calculator compares its usable capacity against the weight of common real loads: sod pallets, round and square hay bales, wet mulch, gravel, and firewood. Attachment deadweight is subtracted, because a grapple consumes capacity before the load does.