Multi-Leg Sling Tension Calculator
Calculate Sling Tension from Load Weight, Sling Angle, and Hitch Type
Use this sling tension calculator as an early rigging geometry prompt. Enter load weight, entered sling legs or basket slings, sling angle from horizontal, hitch type, optional choker angle, optional wire-rope D/d ratio, and optional vertical WLL from the actual tag or manufacturer chart. The app calculates a local static tension prompt and required vertical-WLL review point while showing ASME, OSHA, Crosby/manufacturer, and qualified-rigger source boundaries.
The output is not a lift plan, OSHA compliance result, ASME B30 compliance result, sling tag acceptance, hardware approval, crane setup check, or field authorization. Resolve actual load weight, center of gravity, sling tags, manufacturer hitch charts, inspection status, rigging hardware, crane chart, dynamic effects, site procedure, and qualified lift-plan review before any lift.
Find center of gravity for the load
Center of Gravity Calculator →Check a spreader bar for the lift before qualified design
Spreader Bar & Lifting Beam Sizing Calculator →Check crane rigging capacity and load charts
Crane Rigging Calculator →Read the guide on sling tension and rigging angles
Sling Tension Rigging Guide →How It Works
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Enter Load Weight
Input the best available total load in pounds or US tons. Include rigging and devices below the hook, then verify the value against drawings, scale data, shipping records, or qualified review.
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Select Geometry
Choose the entered legs or basket slings and the sling angle from horizontal. The local static formula uses T = W / (credited paths x sin(angle from horizontal)).
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Select Hitch Prompts
Choose vertical, choker, or basket. Choker angle and wire-rope D/d rows are source-gap prompts only; selected sling manufacturer data controls actual derating.
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Review Source Gaps
Use the warnings, source pointers, and WLL calculator to decide what needs qualified resolution before the lift is planned, documented, or performed.
Built For
- Riggers checking how sling angle changes local static tension before selecting actual tag data
- Lift planners documenting assumptions that still need manufacturer, crane-chart, and qualified review
- Safety teams identifying when low angle, choker, D/d, multi-leg load sharing, or WLL prompts need escalation
- Maintenance crews comparing rough rigging geometries before requesting a formal lift plan
- Training sessions demonstrating why angle, center of gravity, and load sharing must be verified outside a simple calculator
Features & Capabilities
Static Tension Prompt
Calculates local static leg tension from load, credited load-sharing paths, and sling angle from horizontal.
Conservative Load-Sharing Prompt
Credits two load-sharing paths for three-leg and four-leg bridle screens unless qualified lift-plan review proves equalization.
Choker and Basket Boundaries
Shows choker-angle and basket-hitch prompts while warning that load control, D/d, edge protection, and manufacturer charts govern actual use.
Wire-Rope D/d Prompt
Applies a local D/d efficiency prompt for wire rope only, with manufacturer-chart and qualified-review warnings.
WLL Review Screen
Compares an entered vertical WLL against the local required-WLL prompt without treating the result as lift approval.
Source-Aware Export
Exports the local prompt, warnings, assumptions, source pointers, and unresolved source gaps for review.
Assumptions
- Static symmetric lift with equal sling angles, no shock, no wind, no side pull, and no load swing.
- Sling angle is measured from horizontal.
- Three-leg and four-leg bridle prompts credit only two load-sharing paths unless qualified review proves equalization.
- Basket hitch prompts assume ideal balance and two physical legs per credited basket sling.
- Entered WLL is treated as vertical-hitch WLL before local hitch and D/d prompts.
Limitations
- Does not verify load weight, center of gravity, sling length, attachment geometry, equalization, or load control.
- Does not verify sling tag, manufacturer chart, construction, termination, condition, inspection, removal criteria, or service history.
- Does not rate hooks, shackles, master links, below-the-hook devices, or other rigging hardware.
- Does not check crane or hoist load chart, radius, setup, ground support, block weight, or travel path.
- Does not model dynamic loading, shock, wind, swing, side loading, sharp edges, temperature, chemicals, personnel lifting, or site procedure.
References
- ASME B30.9 official source pointer for sling fabrication, attachment, use, inspection, testing, and maintenance.
- ASME B30.26 official source pointer for rigging hardware context.
- ASME B30.5 official source pointer for mobile crane context.
- OSHA 29 CFR 1926.251 construction rigging equipment source pointer.
- OSHA 29 CFR 1910.184 general-industry slings source pointer.
- Crosby rigging information source pointer for practical hitch and WLL terminology.
Frequently Asked Questions
Learn More
Sling Tension: Angle Effects, WLL Reductions, and ASME B30.9 Requirements
How sling angle affects local tension prompts, where WLL and hitch source gaps remain, and why qualified lift-plan review is still required.
Center of Gravity: Calculating CoG for Unbalanced and Composite Loads
How to calculate center of gravity for asymmetric loads, determine sling length ratios for level lifts, and predict tilt angles. Composite body method explained.
Spreader Bar & Lifting Beam: Sizing, Buckling, and Section Modulus
Preliminary sizing of spreader bars (compression) and lifting beams (bending). Euler buckling checks, section modulus requirements, and common tube properties.
Wire Rope Working Load Limits and Sling Design Factors
How to determine wire rope WLL from catalog breaking strength. Design factors by application, hitch type efficiency, D/d ratio, and inspection criteria.
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