CALCULATOR
Rigging Load Calculator
Work out the tension in each leg of a sling arrangement from the load weight, the number of legs and the included angle between them.
What this gives you
Inputs: Load weight, sling angle, number of legs, dynamic factor. Outputs: Tension per leg, resultant direction, safety factor, suggested sling size, angle warning. Sling tension rises sharply with the included angle. At 60 degrees each leg carries the full load; at 120 degrees it carries nearly twice the load.
Tension per leg
—
Ideal share per leg—
Total on the hook—
Required breaking load—
Suggested sling—
Suggested shackle—
tension_per_leg = W ÷ (legs × cos(θ ÷ 2)) × dynamicplanning legs = min(legs, 2) — the load is never perfectly sharedrequired_MBL = tension × 5
∞ RELATED
Put the number to work
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Rope Strength Calculator
Fibre→Breaking strength
Breaking strength, working load and stretch for a given fibre, diameter and duty.
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Knot Strength Calculator
Line breaking strength→Strength at the knot
What a knot costs you, and what the line can safely hold once it is tied.
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INTERACTIVE
3D Studio
See the same numbers as geometry — a rope under load, a splice worked tuck by tuck, force vectors on a rig.
3D Studio
These calculators use simplified models and typical catalogue values. They are for planning and
teaching, not for certifying a lift. Real capacity depends on the specific product, its condition,
the load path and the environment. Where a manufacturer’s rating or a regulation gives a
different figure, that figure governs.