Formula Used
The calculator treats the load as a force. It then applies all selected load factors. Final tension depends strongly on the sling angle.
Capacity factors reduce the marked working load limit. Hitch efficiency also changes usable capacity. Always use current manufacturer guidance before lifting operations.
How to Use This Calculator
- Enter the lifted load and attached equipment weight.
- Select the sling legs and load-bearing leg count.
- Choose a known angle or geometry input method.
- Enter marked capacity and relevant reduction factors.
- Review tension, utilization, warnings, and force components.
- Export the result for checking and lift planning.
Worked Example
| Input | Example value |
|---|---|
| Load | 1,000 kg |
| Load-bearing legs | 2 |
| Angle from horizontal | 60° |
| Dynamic factor | 1.10 |
| Marked WLL per leg | 750 kg |
The adjusted load becomes 1,100 kilograms-force equivalent. Each leg carries roughly 635 kilograms-force at sixty degrees. The result must still pass every field inspection.
Sling Angle Reference
| Horizontal angle | Included angle | Angle factor | Two-leg tension share |
|---|---|---|---|
| 90° | 0° | 1.000 | 50.0% each |
| 60° | 60° | 1.155 | 57.7% each |
| 45° | 90° | 1.414 | 70.7% each |
| 30° | 120° | 2.000 | 100.0% each |
| 15° | 150° | 3.864 | 193.2% each |
Frequently Asked Questions
What is a sling angle?
It is the angle between a sling leg and horizontal. Smaller angles produce greater leg tension. Accurate angle measurement is essential for safer lift planning.
Why does tension increase at shallow angles?
Each leg supplies less vertical force at shallow angles. More total tension becomes necessary. Horizontal compression also rises against the lifted object.
Which angle reference should I use?
Use the reference shown by your lift plan. Horizontal angles are common in tension calculations. The calculator converts vertical and included angles automatically.
What are load-bearing legs?
These are legs assumed to carry the calculated load. Installed legs may not share equally. Conservative rules often reduce the credited leg count.
What does the dynamic factor represent?
It increases load for motion, shock, or acceleration. Smooth lifts may still need allowance. Use values required by your governing procedure.
How is sling capacity derated?
Condition, heat, edges, and bending can reduce capacity. The calculator multiplies selected reduction factors. Manufacturer instructions always override generic estimates here.
What is D/d bending?
It compares bearing diameter against sling diameter. Tight bending can weaken many sling types. Use the correct manufacturer reduction for each connection.
Can unequal load sharing be calculated?
Yes, enter the highest expected leg-load percentage. The calculator applies that share conservatively. Complex lifts require engineered load-distribution analysis.
Does basket hitch capacity always double?
No, ideal geometry may suggest higher theoretical capacity. Connections and bending can reduce it. Use the exact marked and documented hitch rating.
Can this calculator approve a lift?
No, it provides planning estimates and consistency checks. It cannot inspect equipment or conditions. Qualified personnel must approve every lifting operation.
Why compare several sling angles?
The comparison shows how quickly tension changes. It supports safer geometry choices. Greater angles usually reduce leg tension significantly.