Load chart
The manufacturer-supplied table or graph that defines a crane’s rated lift capacity at every combination of boom length, working radius, and counterweight configuration.
A load chart is a crane's rating document. It lists the maximum safe load (in tonnes or pounds) that the crane is approved to lift, for every combination of boom length, working radius, counterweight, outrigger position, and operating configuration the crane supports. Modern load charts run to hundreds of pages — one chart per boom-counterweight-outrigger combination, sometimes one per slewing quadrant if the crane has asymmetric stability.
The chart is what makes a crane legal to operate. A lift that exceeds the relevant load-chart value is by definition outside the manufacturer's structural and stability envelope; doing it risks structural failure, tipping, or the load control system shutting the crane down. Site supervisors and lift planners read the load chart before every non-trivial lift, calculating the actual rated capacity for the specific radius, boom length, and configuration they intend to use.
For used-equipment buyers, the load chart matters in three ways. First, it tells you what the crane can actually do, not just its marketing number. Second, missing or unclear load charts are a red flag — a serious owner keeps the documentation. Third, modifications to the crane (different boom, different counterweight package, different outrigger pads) require a re-rated load chart that reflects the modification.
Kranly listings should include either a scanned load chart, a manufacturer's model number that lets a buyer download the official chart, or the AI-extracted headline numbers from the chart at common radii. If a listing is missing all three, ask the seller before committing.