Sling Angle Load Calculator
Tension in each sling leg at a given angle from vertical, with the angle factor and the sideways pull.
Results
What this tool does
The angle is measured from the vertical, not from the load. Note that the calculation assumes the load is shared equally, which with three or more legs on a rigid load is optimistic: unless the legs are adjustable, two of them usually take almost everything. Rigging is regulated work — use this to understand the numbers, not to replace a competent person's assessment.
Formula
voltage per leg = load ÷ (n × cos θ)
Variables
| Symbol | Meaning | Unit |
|---|---|---|
wl | Load | kg |
nl | Number of legs | — |
an | Angle from vertical | ° |
TL | Tension per leg | kg |
TN | Force | kN |
MF | Angle load factor | — |
HZ | Force | kg |
A60 | Tension per leg | kg |
Worked example
- Load2000 kg
- Number of legs2
- Angle from vertical30 °
- Tension per leg1154.70 kg
- Force11.3237 kN
- Angle load factor1.15470
- Force577.35 kg
- Tension per leg2000.00 kg
Limitations
- For work that must comply with a standard or be signed off, check the result against the applicable code and have it reviewed by a qualified engineer.
- The formula assumes ideal conditions: no friction losses, no air resistance and no efficiency losses unless you enter them.
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
Frequently asked questions
Why is the angle so dangerous?
Because the tension climbs without the load changing, and it climbs fastest exactly where people stop paying attention. At 30 degrees from vertical each leg carries 15 percent more than its share; at 60 degrees it carries double. The last result shows the 60-degree case for your load. Most standards forbid going beyond 60 degrees for this reason, and the sling's marked capacity is only valid for the angle range stamped on the tag.