What a Load Chart Tells You

A load chart is the manufacturer's table of what a crane can actually lift — at every boom length, every radius, every configuration. The headline tonnage painted on the machine is only its capacity at minimum radius with the shortest boom. Everything else lives in the chart.

For tower crane charts within the machine-selection process, see our companion guide on choosing a tower crane with load charts explained.

Load Chart Anatomy

Every load chart combines four variables:

• Operating radius: horizontal distance from the crane's slewing center to the load — the master variable
• Boom length / configuration: main boom angle or length, and whether a jib is fitted
• Rated capacity: the maximum load at the intersection of radius and configuration
• Notes: outrigger position, reeving, wind limits and counterweight configuration

Charts come as radius-along-the-top tables or boom-angle diagrams — both answer the same question: what can I lift, from where, at this configuration?

Reading Capacity at Radius: A Worked Example

Your load is 12 tons, placed 14 meters from the crane's center. The chart allows 9.2 tons at that radius — the lift is impossible in this configuration. Your options: a larger crane class, repositioning to shorten the radius, or a reconfiguration such as a shorter boom. Nothing on site changes the chart; only the setup does.

Derating Factors: Where Charts Shrink

• On rubber vs outriggers: capacity on tires can be half the outrigger rating
• Fly jib fitted: main boom capacity drops, sometimes sharply
• Reeving: the chart assumes the configured fall of rope — fewer parts of line means lower capacity
• Wind: most charts cap operation at 12-14 m/s; sheet materials and formwork derate further
• Side and rear lifts: charts assume lifting over the front unless marked
• Ground bearing: soft or uneven set-up reduces real capacity regardless of the chart

Every factor multiplies against your margin — a lift at 90% of chart capacity in still air on outriggers is a different risk from the same percentage on tires in wind.

Common Load Chart Mistakes

• Planning from the sticker tonnage instead of the radius-specific capacity
• Measuring radius to the boom tip instead of to the load's final position — a load lifted high beside a building can sit at a larger true radius than it appears
• Ignoring rigging weight: hooks, slings and spreader bars count as part of the load
• Forgetting derates: quoting main-boom capacity with a fly jib fitted
• Guessing the load: unreinforced concrete, water tanks and scrap bins are routinely heavier than assumed — weigh or calculate, never estimate

Load Charts and Hire Costs

The chart drives the crane class you pay for. Lifting 10 tons at 8-meter radius might need a 25-ton crane; the same 10 tons at 20 meters needs an 80-ton class — roughly doubling the daily rate. Accurate radius data at booking prevents both expensive errors: over-hiring capacity you never use, and under-hiring a crane that arrives and cannot make the lift, billing mobilization both ways. See our crane hire rates guide for current class pricing, and tower vs mobile selection if the machine type itself is still open.

Who Checks Compliance — and How to Help

A certified operator verifies every lift against the chart as standard practice — it is the core of their training, and operator-inclusive hire packages put that skill in the rate. But the planning support matters: state the load weight, radius and height when you book. Surprises on site — heavier loads, changed positions, improvised rigging — force the operator to stop work. Accurate data at the quote stage turns the load chart from a discovery into a confirmation.

General hire pricing context sits in our crane hire cost guide. Want your lifts checked before the crane books? Request a free consultation — we verify load data against charts as part of quoting.

Frequently Asked Questions