Why a 100 ton crane lifts nowhere near 100 tons on your site
The tonnage on the side of a crane is a best case you will almost never use. It is the capacity at minimum radius in ideal conditions. What the crane actually lifts at your radius is a fraction of the badge, and that is the number to hire by.
7 min read · 2026-08-16
By EHLL Lifting Desk · Editorial, cranes
The tonnage painted on the side of a crane is the most misleading number in lifting. It is the capacity at the minimum radius, with full counterweight, outriggers fully out and the ground level, the best case the machine will ever see and almost never the case on your site. The moment the load sits at a real working radius, the figure on the load chart is a fraction of the badge. Plan a lift by the headline tonnage and you will plan one the crane cannot make; plan it by the chart value at your radius and you will hire the right machine the first time.
The badge is the best case
Rated capacity is quoted at minimum radius, maximum counterweight, full outrigger extension and level ground. That combination almost never exists on a working site, so the badge is a ceiling you do not lift at.
Capacity falls fast as the load moves out
Lifting capacity drops steeply as the radius grows, because the load acts on a longer lever against the crane's stability. The fall is not gentle. A crane rated to lift around 50,000 pounds at a 10 foot radius may manage only about 15,000 pounds at 50 feet, a 70 percent reduction on the same boom. In metric terms, a machine good for roughly 10 tonnes at 5 metres can be down to about 3 tonnes at 15 metres. The headline tonnage and the working tonnage are different numbers, and only the second one lifts your load.
| Radius | Roughly what it lifts |
|---|---|
| Minimum, the badge figure | 100 percent, the marketing number |
| Short working radius | A large fraction of rated |
| Long working radius | Often 30 percent of rated or less |
The conditions that derate it further
Radius is the big one, but it is not the only one. Set up on a 3 degree slope, or rig a jib, and the effective capacity can drop a further 10 to 15 percent. Outriggers that cannot fully extend, or uneven ground, can take 20 percent or more off. And the chart is already conservative on purpose: the listed figure is about 75 percent of the tipping load, so it carries a 25 percent stability margin built in, and good practice keeps the actual load below 75 to 85 percent of the chart on top of that.
Min radius
where the badge figure applies
~70%
capacity lost at long radius
10-15%
off for a slope or a jib
75%
of tipping load, the chart's margin
Near the chart is already the danger zone
If your load is close to the chart value at the working radius, you are not safe with a little to spare, you are at the edge of the built in margin. Size to sit well under the chart at the real radius, not at the badge.
Give us the load, the radius and the height of the lift, and the ground and outrigger conditions, and we will size the crane by what it lifts at that radius with margin, not by the tonnage on the side, so the machine that turns up can actually make the lift.
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