Wire Rope Load Calculator

Formula

• Breaking strength (kN) = coefficient × d²
• SWL = breaking strength / safety factor
• Sling capacity = SWL × angle factor
• Utilization = applied load / sling capacity × 100%

About this calculator

Part of our Mechanical Calculators collection. Beams, bolts, springs, gears, bearings, and core ME calculations.

How it works

Breaking strength uses a wire type and construction coefficient times diameter squared. Safe working load divides breaking strength by your safety factor. Sling angle reduces capacity on multi-leg lifts. Always follow local lifting codes for rigging work.

Enter your values in the inputs above and click CALCULATE. Results appear on the right without a page reload. No login and no server upload.

Worked example

12 mm galvanised 6×19 wire, safety factor 5, single leg.

1. Coefficient = 0.32 kN/mm²
2. Breaking strength = 0.32 × 12² = 46.1 kN
3. SWL = 46.1 × 1000 / 9.81 / 5 = 939 kg

Result: SWL 939 kg on a single vertical leg.

When to use

• Selecting wire rope for lifting or rigging
• Checking sling capacity on multi-leg lifts at an angle
• Verifying applied load against SWL before a lift

Limitations

• Coefficients are approximate; use manufacturer catalog data for certification
• Does not cover termination efficiency or dynamic loading factors
• Always follow local lifting regulations and qualified rigger sign-off

FAQ

What safety factor is typical?

General lifting often uses 5:1 on breaking strength. Critical lifts may require higher factors per code.

Why does sling angle matter?

Legs at an angle from vertical share load through cosine components. Two-leg and four-leg factors reduce rated capacity accordingly.