Lifting and Hoisting Inspection Calculator

Calculator Inputs

Example data table

Formula used

• Per-leg tension estimate: T = Load / (legs × V)
• Vertical component: if angle is from horizontal, V = sin(angle); if from vertical, V = cos(angle).
• Leg utilization: T / Sling WLL. Hardware utilization: Load / Hardware WLL.
• Capacity margin check: required minimums apply your safety factor: Required = Demand × SafetyFactor.
• Checklist score: starts at 100; unchecked items subtract weighted points. Any critical unchecked item drives a fail decision.
• Adjusted interval: AdjustedDays = BaseDays × EnvironmentFactor (Normal 1.00, Harsh 0.75, Extreme 0.50).

This tool estimates rigging tension for planning and inspection screening. Always follow your local regulations, manufacturer limits, and approved lift plans.

How to use this calculator

1. Enter the planned configuration: rated capacity, load, legs, and angle reference.
2. Provide the lowest Working Load Limits for slings and hardware in the lift path.
3. Set a safety factor that matches your site rules and lift category.
4. Enter the last inspection date, interval, and environment severity to schedule the next due date.
5. Tick every checklist item that is verified acceptable during inspection.
6. Press Submit to see pass/fail status, score, due date, and utilization ratios.
7. Use Download CSV or Download PDF to keep records with your lift plan.

Inspect routinely, calculate conservatively, and lift only when compliant.

Professional guidance article

1) Why inspection plus planning must work together

Lifting and hoisting incidents often start with small defects and optimistic assumptions. This calculator combines a practical checklist score with capacity screening so crews can confirm readiness before the hook leaves the ground. Use it as a pre-lift decision aid, not a substitute for manufacturer limits, local rules, or an approved lift plan.

2) What the checklist score represents

The checklist begins at 100% and subtracts weighted points for each unchecked item. Higher-weight items reflect higher consequence and likelihood. Any critical item left unchecked forces a fail decision because defects like a damaged hook latch, compromised slings, or ineffective brakes can escalate quickly under dynamic loading.

3) Angle data: how sling angle drives tension

Angle is a measurable driver of rigging demand. With two legs and a 6.5 t load, tension per leg is about 3.75 t at 60° from horizontal (since sin60° is 0.866). The same lift at 30° becomes about 6.5 t per leg, often exceeding WLL even when the load weight stays unchanged.

4) Capacity screening with a safety factor

To promote conservative decisions, the calculator applies a user-defined safety factor to minimum required capacities. For example, a 1.25 factor means the sling leg, hardware, hoist limit, and equipment rating should each exceed 125% of demand. This helps manage uncertainty from load estimates, wear, and operational variability.

5) Inspection intervals and environment severity

Inspection scheduling is risk-based. A base 30-day interval becomes 23 days in harsh service (30 × 0.75) and 15 days in extreme service (30 × 0.50). Use harsh for dust, chemicals, marine exposure, or frequent shock loading. Use extreme for continuous corrosion or severe abuse.

6) Competent person, tags, and records

Administrative controls matter. A competent person confirmation, visible tag/ID, and accessible certificates turn inspection activity into traceable compliance. If any of these are missing, the calculator flags an administrative fail. That protects crews from “unknown condition” gear and supports audits and incident investigations.

7) Interpreting utilization ratios in the field

Utilization ratios compare demand to limits. Ratios below 1.000 indicate the input limits exceed the calculated demand. Ratios approaching 0.90 should prompt extra caution: verify units, confirm angle measurement method, re-check load weight, and consider increasing WLL or reducing angle severity with spreader beams.

8) Turning results into actions and records

Use the result panel as a brief lift gate: PASS supports proceeding when controls remain unchanged; FAIL requires correction before lifting. Export CSV for daily logs and trend reviews, and export PDF for lift packets. Consistent records improve predictive maintenance and help standardize safe lift decisions across teams.

Frequently asked questions

1) What units should I use for capacities and load?

Use consistent units for every capacity and the load. This calculator’s example uses tonnes. If you use kilograms or pounds, keep everything in that same unit system.

2) How do I choose “from horizontal” versus “from vertical”?

Select the option that matches how your crew measures angle on site. Many rigging charts quote sling angles from horizontal. If your inclinometer reads from vertical, choose that reference.

3) Why did I fail when my load is below rated capacity?

A lift can fail due to sling tension at low angles, low WLL hardware, overdue inspections, missing records, or critical defects. Rated capacity alone does not confirm rigging integrity.

4) Does the per-leg tension include dynamic effects?

No. It is a static planning estimate based on angle geometry. Shock loading, side loading, snatch picks, and travel can increase real forces, so keep conservative margins.

5) What safety factor should I enter?

Use your site’s lifting procedure or engineered lift plan. Many teams apply 1.10 to 1.50 depending on lift criticality, uncertainty, and inspection confidence.

6) How should I treat multi-part lines or reeving?

Enter the governing hoist limit you are using for the planned configuration. If you have a charted line pull by reeving, use that limit as the hoist capacity input.

7) Can I store the results for audits?

Yes. Run the calculation, then download CSV or PDF. Keep the files with your lift plan, daily inspection log, and any defect correction records.