Crane Lift Utilisation Calculator
See at a glance how hard a crane is working on a planned lift. Enter the gross lift mass and the rated capacity read from the load chart at the working radius, and this tool returns the utilisation percentage, the remaining capacity and a plain OK / review / OVERLOAD verdict against common procedure limits.
Enter Values
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the gross lift mass in kilograms — the load plus all below-the-hook gear and contingency (use the Gross Mass Estimator first if you have not totalled it).
- Enter the crane's rated capacity at the ACTUAL working radius, boom length and configuration for the lift, read straight from the manufacturer's load chart.
- Read the utilisation %, the remaining capacity and the status band; treat anything above about 75–90% as needing extra scrutiny in your lift plan.
How it works
Utilisation = gross lift mass ÷ rated capacity × 100. Remaining capacity = rated − gross. The status is banded: above 100% is an OVERLOAD, 90–100% is flagged review/marginal, and at or below 90% is reported OK. The bands are a guide — your site procedure may set a tighter cap (commonly 75–90%) and stricter limits again for tandem, blind or personnel-adjacent lifts.
Worked example
Worked example. A gross lift mass of 9,350 kg on a crane rated 12,000 kg at the working radius gives utilisation = 9,350 ÷ 12,000 × 100 = 77.92%, with 2,650 kg remaining — OK for a routine lift. If the gross rose to 11,500 kg the utilisation would be 95.83% (only 500 kg spare), which the tool flags as review/marginal.
Common mistakes
- Reading rated capacity at the wrong radius — capacity drops sharply as the radius grows, so a figure taken at a shorter radius will overstate what the crane can actually lift.
- Treating a high utilisation as automatically safe just because it is under 100% — dynamic loads, side loads, out-of-level and wind all erode the real margin and are not in this ratio.
- Forgetting to include all below-the-hook gear and contingency in the gross mass, which understates utilisation.
Frequently asked questions
What utilisation is safe to lift at?
There is no single number — it depends on the crane, the lift class and your procedure. Many operations cap routine lifts around 75–90% of chart and apply tighter limits to complex, tandem, blind or personnel lifts. This tool flags 90–100% as review and over 100% as overload, but the lift plan and the licensed crew set the actual limit for the job.
Does a utilisation under 100% mean the lift is fine?
Not on its own. The chart rating assumes a level, firm set-up, still air and a static, plumb load. Snatch/shock loading, swinging, side pull, an out-of-level crane, wind on the load and poor ground bearing all reduce the effective capacity. Keep a margin, follow the crane's wind and configuration limits, and have a competent person plan the lift to AS 1418 / AS 2550.
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Tip: Enter any known values to calculate the remaining results.
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