RigMaster is a rigging calculator for working riggers, crane operators and signal persons. Every calculation runs on the phone, so no signal is needed on site, and there is no login or sign-up.

Sling Tension works as a sling angle calculator for two-leg picks, either by angle or by sling length and height, which is the way you actually measure on the job. A live sling diagram shows the angle and the tension on every leg. Hitch Capacity gives vertical, choker and basket capacity from the rating on your own sling tag. The Angle Reference is the tension multiplier table, always in your pocket. Results are built on first-principles trigonometry, with warnings at 45 degrees and hard alerts below 30 degrees, following standard rigging practice and ASME B30.9 guidance.

Units switch at any time between kilograms and metres or pounds and feet. It is a universal app, with a two-column layout on iPad in any orientation.

The core app includes Sling Tension, Hitch Capacity and the Angle Reference table. The optional Pro upgrade turns it into a rigging bridle calculator, adding three and four-leg bridles with rigid or flexible load sharing, unequal legs with centre of gravity offset, a load weight estimator for steel, concrete, aluminum and other materials by shape and dimensions, and a lift plan PDF. The lift plan turns any calculation into a one-page document with the diagram, inputs, results, room for notes and three signature lines for prepared by, signature and date, which you can share straight to the supervisor.

RigMaster is an estimation aid for qualified riggers. Always follow the sling tag, the load chart and your site's rigging plan.