How to pick the
right crane tonnage

The most expensive crane on a jobsite is the one that is too small. The second most expensive is the one that is much too big. Sizing the right crane for a pick is the difference between a clean day and a callback.

Three numbers drive crane sizing: the load weight, the lift radius (distance from the crane center pin to the pick), and the pick height. Load weight includes the actual piece plus any rigging — slings, spreader bars, shackles, tag lines.

For most picks, target the crane at 75% of its rated capacity at the actual lift radius — not at the radius the load chart cover says. Capacity drops off steeply with radius; a 90-ton crane might only be a 30-ton crane at 80 feet of radius. Always size off the actual pick parameters.

Step 1: Confirm the load weight (including rigging)

Get the actual load weight from the manufacturer or the steel detailer, not an estimate. Add the rigging weight: a typical HVAC rooftop unit needs ~500 lb of rigging; a refinery exchanger needs an engineered spreader that can run multiple thousand pounds. Round up.

Step 2: Measure the lift radius accurately

The crane has to sit somewhere, and from where it sits, the load is some distance away. That distance — pin to pick — is the lift radius. Walk the jobsite, account for setback from buildings or fences, and measure honestly. Lift radius is the single biggest variable in crane capacity.

Step 3: Apply the 75% rule

Most contractors apply a working capacity of 75% of rated capacity at the actual radius. Owner critical-lift criteria may push this lower (60–66%) for picks over live units or near energized equipment. Engineered lift plans confirm the specific capacity for the specific pick.

Step 4: Call dispatch

A two-minute conversation with a dispatcher can save a wasted morning of crane sizing. Tell us the pick weight, radius, height, jobsite type, and date — we will recommend the right crane (or tell you if a different rig altogether is a better fit).