
RigMaster: Rigging Calculator
Sling Tension & Load Weight
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About
RigMaster is the rigging calculator built for working riggers, crane operators, and signal persons.
IPAD & UNITS
• Universal app — two-column layout on iPad, any orientation
• Metric or imperial — kg and metres or lb and feet, switch any time
• Live sling diagram with the angle and tension on every leg
FREE CALCULATORS
• Sling Tension — 2-leg picks by angle, or by sling length & height (the way you actually measure)
• Hitch Capacity — vertical, choker, and basket capacity from YOUR sling's tag rating
• Angle Reference — the tension multiplier table, always in your pocket
PRO CALCULATORS
• 3 & 4-leg bridles with rigid/flexible load sharing
• Unequal Legs / CoG Offset — tension per leg when the center of gravity isn't centered
• Load Weight Estimator — steel, concrete, aluminum and more, by shape and dimensions
• Ad-free
Built on first-principles trigonometry with warnings at 45° and hard alerts below 30°, following standard rigging practice (ASME B30.9 guidance).
RigMaster is an estimation aid for qualified riggers. Always follow the sling tag, the load chart, and your site's rigging plan.
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What's New in RigMaster
1.1.0
July 30, 2026
iPad support: every calculator now runs in a two-column layout, in any orientation. Metric units: work in kg and metres — or stay in lb and feet. Switch any time in Settings. New sling diagram: see the pick, the angles and the tension on every leg while you type. Angle reference chart: watch the multiplier climb as the angle drops below 45°. Bigger, clearer results, plus light/dark themes and text-size options for sunlight and gloves. RigMaster is now translated into 13 languages.
MoreSubscription plans
Pro Weekly
All rigging calculators and reference charts
$4.997 Days
1
In-App Purchases
$39.99
RigMaster Pro
Every Pro calculator and chart. Forever.




