Crane Lift Plan Quick-Math

Gross load, sling tension, percent of chart, and 75 / 90 percent flag. The crane manufacturer's load chart governs.

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Formula and source

Gross load = load + rigging + block + jib_deduct. Per-leg sling tension L = W / (n × sin(theta/2)) (basket / bridle form). Percent of chart = gross / chart_capacity × 100. Flags: < 75% green, 75-90% yellow, ≥ 90% red. Refuses to render an output without the user-entered chart capacity (the tool never reproduces a load chart).

ASME B30.5 (Mobile and Locomotive Cranes) by name and section. ASME B30.9 (Slings) for the per-leg formula. OSHA 29 CFR 1926 Subpart CC (cranes and derricks) by section.

Audience

This tile is built for carpentry and the adjacent professions in the Carpentry and Construction group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.

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Posture

Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.