← Niches
Rigging reference

Sling Angle Calculator

See how the sling angle multiplies the tension in each leg — the lower the angle, the higher the force.

Short answerTension per leg = Load ÷ (N × sin θ), where N is the number of legs and θ the angle from horizontal. The load factor 1 ÷ sin θ is 1.15 at 60°, 1.41 at 45° and 2.0 at 30° — never rig below 30°.

Want this on your own domain?

We build this calculator as an embeddable tool — engineered, SEO- and AI-ready, delivered in 5 business days for a flat $2,800.

Get yours in 5 days

How it's calculated

Sling legs at an angle share the load along their length, so each leg carries more than its vertical share. The horizontal component grows as the angle to horizontal shrinks, multiplying tension by 1/sin θ. Below 30° the forces climb steeply and are prohibited by good practice.

Tension per leg = Load ÷ (N × sin θ) Load factor = 1 ÷ sin θ θ = angle from horizontal
Worked example
  1. 2,000 lb, 2 legs, 60°.
  2. Per leg = 2,000 ÷ (2 × 0.866) = 1,155 lb.

Reference tables

Load factor by sling angle (from horizontal)

Anglesin θLoad factor
90°1.0001.00
60°0.8661.15
45°0.7071.41
30°0.5002.00

A number the tables do not give: dropping the sling angle from 60° to 30° doubles the tension in each leg for the same load.

See a live tool in action

The interactive version of this calculator is on our build queue. Meanwhile, these live example simulators show exactly how yours would look and behave on your own domain:

Conduit Fill · NEC▶ LIVE CALCULATOR Storage Rack quote-simulator▶ OPEN DEMO Packaging / box simulator▶ OPEN DEMO

FAQ

Angle from horizontal or vertical?

This uses the angle from horizontal, the ASME convention. A 60° sling is steep; a 30° sling is shallow and highly loaded.

Why never below 30°?

The load factor exceeds 2.0 and rises sharply, overloading slings and hardware; ASME B30.9 practice prohibits it.

Do all legs share equally?

Only with symmetric geometry and rigid loads. With three or four legs, assume the load rests on the two most-loaded legs unless it is truly rigid.

Does the hitch matter?

Yes — choker and basket hitches change the effective capacity; apply the sling’s rated reduction on top of the angle factor.

This page is a reference aid. Always verify against ASME B30.9 and the sling manufacturer data. Figures shown are for orientation, not a stamped design.

Build it for your catalog

Put this calculator on your domain so the engineers who run it land on your site — not a competitor's. See how it works or start the conversation.