Truss Load Calculator (Working Load Limit)
Calculate truss utilization based on point loads (lights, motors, video panels, etc.) against the manufacturer's Working Load Limit (WLL). Uses the entertainment industry standard 10:1 safety factor (ESTA/PLASA recommendation). Built for production riggers, technical directors, and tour crews.
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Last reviewed: April 2026Report an error
From manufacturer chart.
10:1 default.
Point Loads
Within Limits ✓
47% utilized
Total load: 700 lbs of 1,500 lbs maximum (SF 10:1). Capacity remaining: 800 lbs.
Total Load
700 lbs
Max @ 10:1
1,500 lbs
Utilization
47%
⚠ All rigging must be inspected and signed off by an ETCP-certified rigger.
Load Contribution by Item
Capacity Utilization
700 lbs of 1,500 lbs max (47%) — safe headroom
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The Formula
- WLL_chart = Working Load Limit from manufacturer at this span
- SF = Safety factor (10:1 industry standard for entertainment)
- total_load = Sum of all point loads (lights, motors, video)
Source: ANSI E1.2-2012 — Entertainment Technology Aluminum Trusses ↗
How to Use This Truss Load Calculator
- 1Enter the truss span between supports (in feet).
- 2Enter the WLL from the manufacturer's load chart at that span.
- 3Add each point load: name, weight per item, count.
- 4Optionally adjust safety factor (default 10:1 industry standard).
- 5Read utilization, remaining capacity, and warnings.
Frequently Asked Questions
- The maximum weight a truss section can safely support, derived from ultimate breaking strength divided by safety factor. ESTA standard for entertainment truss is 10:1 — meaning a truss with a 10,000 lb ultimate strength has a 1,000 lb WLL.
- Entertainment riggers fly equipment over people. The 10:1 factor accounts for dynamic loads (swing, motor jerks), repeated stress cycles, and the consequences of failure. Static structural engineering typically uses 5:1 — entertainment is more conservative.
- No — you must use the WLL value from the manufacturer's load chart for YOUR specific span. Truss capacity decreases with longer spans. A 30ft span carries far less than a 10ft span on the same truss.
- YES, ALWAYS. This calculator is a planning tool. Real rigging requires an ETCP-certified rigger or licensed structural engineer who evaluates: truss condition, attachment points, dynamic loads, secondary safety, building structure, and applicable building codes. Never fly without certified sign-off.
- Manufacturer WLL is typically based on a uniformly distributed load. Concentrated point loads at the center of a span have higher impact and should be derated. This calculator treats all loads as point loads (conservative). For exact UDL math, consult the manufacturer.
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