Rigging Calculator

A reference and educational tool for sling (rigging) calculations on lifting sites.
Enter the load, number of legs, sling angle and hitch type to get the required WLL per leg and the tension and force components right away.

■ Required WLL
· Choose the total lifting load (W), number of legs (1 leg / 2 legs / 2 legs asymmetric / 3–4 legs), the sling angle and the hitch type (Vertical / Choker / Basket) to calculate the required WLL per leg.
· Choker hitch applies an efficiency of 0.8, and this is shown on the result screen.
· 2 legs (asymmetric): enter each leg's angle from vertical (β1, β2) to see the required WLL per leg and the imbalance.
· When the sling angle leaves the recommended range, the result screen shows a graded warning.

■ Tension and force components
· Shows the tension per leg (T) and the vertical and horizontal components (V, H) as a diagram and a table.
· See how tension grows as the angle opens.

■ Protractor
· Tilt mode: measures a sling leg's angle from vertical (β) with the phone's motion sensor.
· Camera mode: align the on-screen reference line with the sling leg to read the angle.
· Send the measured included angle, β or tension factor straight to the calculator input.
· Camera permission is needed only for camera mode. Tilt mode and all calculations work without it.

■ Scientific calculator and unit conversion
· Trigonometric and inverse trigonometric functions, logarithms and exponents, roots and powers, factorial, with DEG / RAD / GRAD angle units. Recent results can be recalled and reused.
· Unit conversion: length, mass, force. Includes the t ↔ kN conversion used in rigging, and results can be sent to the calculator.

■ Who it is for
· Riggers and signallers on crane and hoist lifting sites
· Safety managers and supervisors reviewing lift plans
· Trainees learning how sling angle relates to tension

■ Features
· Calculations and the protractor work offline (an internet connection is needed only to show ads).
· Korean and English, switchable from the menu at any time.
· Educational calculation logic based on publicly available rigging references.

■ Standards note
· The choker efficiency of 0.8 follows LEEA guidance (COPSULE). Other standards or manufacturers may apply a different choker reduction. Check the standard, manufacturer data and site rules that apply to your work.
· Loads and required WLL are shown in tonnes (t); the unit converter covers t ↔ kN.

■ Safety notice (please read)
Results from this app are for reference and educational use only. Actual lifting and rigging work must follow the applicable standards and be reviewed by a qualified person; do not decide whether a lift may proceed based on this app alone.
Before any lift, check the manufacturer's specifications of the gear in use, its inspection status, the site conditions, and the applicable regulations and company rules, and follow the decision of the person in charge on site. Input errors, measurement errors and damaged gear can make real values differ from the results shown.
Protractor readings depend on the phone's sensors and camera alignment and are for reference only.

■ Ads
This app is free and shows Google AdMob ads; the advertising ID may be used to serve them. Users in the European Economic Area, the UK and Switzerland are shown a consent screen for ad-related data processing; all features remain available without consent. Users in those regions can change or withdraw consent at any time under "Privacy options" in the app menu.
Privacy policy: https://jin-devacc.github.io/riggingcal-privacy/

■ Contact
contact@riggingsafety.org