Rigging & Bridle Sling Tension Solver
Solve per-leg tension in bridle slings from load weight, number of legs, and sling angle from horizontal, with angle derating and rated-capacity checks.
Lift Configuration
Bridle Tension Results
Tension per Leg
—
lb per sling leg
Load Share per Leg
lb (W ÷ effective legs)
Derated Capacity at θ
—
WLL × sin(θ), lb
Horizontal Force / Leg
—
lb on each anchor point
Utilization
—
tension ÷ derated capacity
Safety Check
—
vs. rated capacity per leg
| Sling Angle (from horizontal) | Derating Factor sin(θ) | Derated Capacity % | Guidance |
|---|---|---|---|
| 90° (vertical) | 1.000 | 100% | Full rated capacity |
| 60° | 0.866 | 86.6% | Typical preferred minimum |
| 45° | 0.707 | 70.7% | Use with care |
| 30° | 0.500 | 50% | Absolute minimum — avoid |
| 15° | 0.259 | 25.9% | Prohibited for most lifts |
| 10° | 0.174 | 17.4% | Extreme loading — never use |
Formula Breakdown
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Informative Guides & Helper Articles
Best Practices for Rigging & Sling Tension
Rigging best practices: angle control, sling selection, load handling, inspection, and lift planning for safe overhead lifting.
Read Article →Common Errors in Rigging & Sling Tension
Fix the most dangerous rigging mistakes: dividing load by legs, ignoring sling angle, 4-leg overestimation, and wrong angle measurement.
Read Article →Future Trends in Rigging & Lifting Technology
Smart slings, load-cell telemetry, and crane control systems: the future of rigging tension monitoring and lifting safety.
Read Article →Ultimate Guide to Rigging & Sling Tension
Master bridle sling trigonometry, angle factors, load sharing, and capacity derating for safe rigging and lifting operations.
Read Article →Top Optimization Tips for Rigging Operations
Optimize rigging: design lifts with steep angles, balance loads, use spreader bars, and right-size slings to cut tension and add safety.
Read Article →How to Use the Rigging Tension Solver
Computes per-sling loads in multi-leg rigging from load weight and sling angles.
- Enter load weight and number of slings.
- Enter each leg angle from horizontal.
- Read per-sling tension; verify against WLL ratings.
Sling Angles Multiply Tension
Per-leg tension = (Load / legs) / sin(theta): at 60 degrees each of two legs carries 1.155x half the load; at 30 it is 2x; at 15, 3.86x. Example: 4,000 kg on two slings at 45 degrees = (2,000)/0.707 = 2,828 kg per leg - 41% more than the naive half, checked against WLL (breaking / design factor, 5:1 chain). Practice bars legs below 30 degrees; the fix is a spreader bar, keeping tensions at the mathematical minimum.
Rigging Tension Solver FAQ
Why do shallow angles multiply load?
Vertical support = tension x sin(angle). At 30 degrees each leg pulls twice its share; at 15, nearly four times.
Minimum sling angle?
Never below 30 degrees from horizontal. Below that, tension and instability spike - use a spreader bar.
WLL vs breaking strength?
WLL = breaking / design factor (5:1 chain, 7:1 many synthetics). Re-rate for chokes and angles.