The door sticker

The label lists GVWR, GAWR for each axle, and the tire and wheel specification those ratings assume. Payload on a specific truck is GVWR minus that truck’s curb weight, and options already installed have already spent part of it.

A published maximum is the best cell in the chart, measured on a configured test truck. Your truck is one row, plus floor mats, a tonneau, a bigger battery, and the people in the cab. If the sticker and a web listing disagree, use the sticker.

This site will show GVWR and axle ratings when a chart or label source names them for that model year. Until then the field stays empty on purpose.