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What a Load Chart Is and How an Operator Reads It
In Short
A load chart trades radius against boom length. Capacity drops as the load moves out. Deductions for hook block, rigging and jib come off first.
3 min readUpdated July 2026
A load chart is a table that pairs working radius with boom length and shows what the crane can hold in that exact configuration. Capacity falls as radius grows. Separate charts cover outrigger position, counterweight and boom setup, and the weight of the hook block, rigging and jib is deducted first.
Rows, Columns and a Falling Number
A load chart is a grid. Down one side is the working radius, which is the horizontal distance from the crane's center of rotation out to the load. Across the top is boom length. Where a row meets a column there is a rated capacity for that combination.
The thing to understand is the shape of the numbers, not the numbers themselves. As you move down the radius column, capacity falls, and it falls faster than most people expect. Doubling the distance out does not halve the number. It cuts it a great deal more than half. A load that a crane handles comfortably beside the truck can be flatly out of reach across a yard.
This is why a rating on the side of a truck answers almost nothing on its own. Elsewhere on this site there is a page explaining what the 22-ton, 40-ton and 142-foot figures mean for a customer. Here the point is narrower: those headline numbers are one cell on a grid with hundreds of cells, and the cell that matters is the one matching your job.
One Chart Per Configuration
There is not one chart. There is a book of them, and the operator has to be on the right page before reading a single value.
Outrigger position gets its own chart. Fully extended is one set of numbers. Partially extended is a different, smaller set. Retracted is smaller again. Counterweight configuration gets its own chart too, because how much weight is on the back of the truck changes what the front can hold.
Boom configuration matters the same way. Main boom is one chart. Main boom with a jib attached is another, and simply having a jib pinned on changes the numbers even when the jib is not in use. Then there is the quadrant: over the rear, over the side and over the corner are not equal, and many machines have separate values for each.
So the honest answer to how much a crane can lift is always a question back. Extended how far, at what radius, over which quadrant, with what on the end of the boom.
- Working radius, measured from the center of rotation
- Boom length actually deployed
- Outrigger extension, full or partial
- Counterweight configuration on the truck
- Jib attached or stowed
- Quadrant: over the rear, side or corner
What Comes Off Before You Compare
The number in the chart is not the weight you get to hang on the hook. It is gross capacity, and several things come off it first.
The hook block and any overhaul ball are deducted. The rigging is deducted: slings, shackles, spreader bar, everything between the hook and the load. A jib comes off even when it is folded and stowed alongside the boom, because it is still weight out on the end. Whatever remains after those deductions is what is available for your item.
That gap surprises people. On a long-radius pick the deductions are a meaningful share of what the chart showed, and a job that looked like it had margin turns out to have very little.
The chart is the governing document. Not experience, not a feel for the machine, not what worked last time on a job that looked similar. The operator reads it for the setup that exists on the day, with a measured radius rather than an estimated one, and if the load does not fit under the number after deductions, the setup changes or the job does not happen.
How the job runs
Our Process
Step 1: Fix the Setup You Will Actually Use
Outrigger extension, counterweight and boom configuration are decided from the ground available, then the matching chart is selected. Reading the wrong page is the fastest way to a wrong answer.
Step 2: Measure the Working Radius
Radius is measured from the center of rotation to where the load will hang, not paced off or guessed from a photo. Both the pick radius and the set radius get checked.
Step 3: Find the Row and the Column
The boom length needed for that radius and height leads to a column, the radius leads to a row, and the intersection gives gross capacity for that quadrant.
Step 4: Subtract Before You Compare
Hook block, rigging and any jib weight come off the gross figure. Only the remainder is compared to the load, and it has to clear with margin, not sit exactly on the line.
Scope
What Is Included
- Chart selected for the actual outrigger and counterweight setup
- Measured pick radius and set radius rather than estimates
- Boom length and quadrant confirmed before the value is read
- Hook block, rigging and jib weight deducted from gross capacity
- A re-check if the setup position or the load weight changes on the day
Answers
Frequently Asked Questions
Can you just tell me the capacity at a given distance?
Not honestly, and not over the phone. The value depends on boom length, outrigger extension, counterweight, quadrant and what is on the end of the boom. Give us the weight, the distance and the setup room and the chart gets read for that combination.
Why does capacity drop so fast as the load moves out?
Because the load acts on a lever. Every foot farther from the center of rotation increases the tipping effect, so the rated value falls sharply rather than in a straight line. Radius is usually the deciding factor, more than raw weight.
Does the rigging really come out of the capacity?
Yes, all of it. Hook block, overhaul ball, slings, shackles and a spreader bar are all deducted from the chart figure before it is compared to your item. On a long-radius pick that deduction is not trivial.
Does having a jib on change anything if we do not use it?
It does. A stowed jib is still weight carried out on the boom, and the chart for a machine with a jib pinned on is different from the chart without it. The operator reads whichever one matches the truck that day.
More Guides
- Capacity and Reach ExplainedA 40-ton crane will not lift 40 tons at full boom. Here is what capacity ratings, load radius and 142 feet of reach actually mean for your job.
- Choosing the Right CapacityChoosing between the 22-ton and 40-ton boom truck is weight, distance and setup room together. Here is how the call gets made and what to send.
- Rigging FundamentalsHow slings, shackles and spreader bars attach a load to the hook. Sling angle, center of gravity, gear inspection, and who supplies the rigging.
- Lift Planning BasicsWhat a lift plan contains, why even a small residential pick gets one, and what a written plan looks like when a project file needs documentation.
- How Mobile Crane Service WorksA mobile crane brings the machine and the operator to your site. Here is what happens from the first phone call through setup, the pick and pack up.
- Capacity and Reach ExplainedA 40-ton crane will not lift 40 tons at full boom. Here is what capacity ratings, load radius and 142 feet of reach actually mean for your job.
- Site Preparation ChecklistWhat to clear, move, unlock and check before a crane arrives. A prepared site keeps the visit short and stops problems being found at the worst moment.
- What to Expect on Lift DayA walkthrough of lift day from arrival to departure, including how long each stage takes, what you can do, and why setup takes longer than the pick.
- HVAC Unit Crane Placement GuideHow rooftop package units and condensers get craned on and off, how the work is sequenced with your HVAC contractor, and what a curb mismatch means.
- Truss Lifting Process and SafetyHow roof trusses get set with a boom truck: staging bundles, spreader bars, bracing, wind limits and keeping the crane in one position along the wall line.
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