Lift Input Form
Enter values in metric units. This tool is for preliminary planning and education. Final lift decisions must follow certified load charts and site controls.
Capacity Curve Graph
The chart plots estimated net allowable payload against lift radius using your current factors. A larger radius usually lowers lifting capacity.
Formula Used
Gross adjusted capacity = Rated capacity × (Reference radius ÷ Actual radius)deration exponent × Outrigger factor × Ground factor × Slew factor
Net allowable payload = (Gross adjusted capacity ÷ Dynamic factor ÷ Wind factor ÷ Safety factor) − Rigging weight
Available margin = Net allowable payload − Load weight
Utilization = Load weight ÷ Net allowable payload × 100
This calculator provides a planning estimate only. Actual crane lifting capacity must always be confirmed from the manufacturer load chart, rigging study, site conditions, and a qualified lift supervisor.
How to Use This Calculator
- Enter the crane rated capacity from a known chart point.
- Enter the reference radius tied to that rated chart value.
- Fill in actual lift radius, boom length, and boom angle.
- Add the lifted load weight and the rigging or hook weight.
- Adjust safety, dynamic, wind, ground, outrigger, and slew factors.
- Click calculate to view net allowable payload and utilization.
- Review warnings, export the report, and compare options on the graph.
- Verify the final lift with formal engineering checks and approved load charts.
Example Data Table
| Rated Capacity (t) | Actual Radius (m) | Load (t) | Rigging (t) | Net Payload (t) | Utilization (%) | Status |
|---|---|---|---|---|---|---|
| 35.00 | 6.00 | 9.00 | 0.60 | 18.74 | 48.03 | Within Estimated Planning Limit |
| 50.00 | 8.00 | 11.00 | 0.90 | 17.45 | 63.04 | Within Estimated Planning Limit |
| 75.00 | 10.00 | 16.00 | 1.10 | 21.98 | 72.78 | Within Estimated Planning Limit |
Frequently Asked Questions
1. What does this crane lifting capacity calculator estimate?
It estimates net allowable payload after adjusting rated capacity for radius, rigging, safety, dynamic loading, wind, and site reduction factors.
2. Is this enough for a real lift decision?
No. Real lifts must use the manufacturer load chart, site-specific controls, rigging verification, and qualified supervision before work starts.
3. Why does capacity drop when radius increases?
A wider radius increases overturning moment. As the load moves farther from the crane center, the safe lifting capacity usually decreases.
4. Should rigging weight be included?
Yes. Slings, shackles, spreader bars, hooks, and blocks add suspended weight and reduce the remaining payload available for the lifted item.
5. What is the safety factor doing here?
It reduces usable capacity to add planning conservatism. A higher safety factor gives more buffer against uncertainty and operational variation.
6. What do ground and outrigger factors represent?
They represent support quality. Poor mats, uneven setup, or reduced outrigger extension can lower the crane’s practical lifting performance.
7. Why is boom angle shown with reach and tip height?
Boom angle helps estimate horizontal reach and hook elevation. These values help you compare geometry, clearance, and radius feasibility.
8. Can I export the result?
Yes. After calculation, you can download a CSV summary or a compact PDF report for planning reviews and recordkeeping.