Capacity at Radius — Capacity at a Radius
Approximate available capacity at a working radius from the moment rating, capped by max line pull.
The same arithmetic forward: moment ÷ radius ≈ available capacity, capped by the max-load winch limit close-in. Real charts step rather than glide because of reeving changes (2-fall to 4-fall); treat this smooth curve as the envelope between chart points, never above them.
Formula
Note: Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
Approximate available capacity at a working radius from the moment rating, capped by max line pull. A free crane load, wind & rigging safety tool — no sign-up, no upload, instant results in your browser.
About Capacity at Radius — Capacity at a Radius
Capacity at Radius — Capacity at a Radius computes the governing relationship cap(r) ≈ min(M/r, max line pull) live as you type. The same arithmetic forward: moment ÷ radius ≈ available capacity, capped by the max-load winch limit close-in. Real charts step rather than glide because of reeving changes (2-fall to 4-fall); treat this smooth curve as the envelope between chart points, never above them. Defaults are pre-filled with realistic values for this exact scenario, and the worked example substitutes your numbers step by step so the math is never a black box.
How to use Capacity at Radius — Capacity at a Radius
- 1Enter your values — Rated load moment, Working radius, Max capacity (close-in) (sensible defaults are pre-filled).
- 2Read the live results: Approx. capacity.
- 3Check the "with your numbers" line to see cap(r) ≈ min(M/r, max line pull) substituted step by step.
- 4Adjust inputs until the scenario matches yours, then copy or share the result.
Why use Capacity at Radius — Capacity at a Radius?
- ✓Instant, free and private — every calculation runs client-side in your browser; nothing is uploaded
- ✓Built on the stated formula cap(r) ≈ min(M/r, max line pull) with authoritative sources cited on the page (EN 13001 / EN 14439 — Crane design & tower crane standards; ASME B30.5/B30.9/B30.20 — Cranes, slings and below-the-hook devices)
- ✓The same arithmetic forward: moment ÷ radius ≈ available capacity, capped by the max-load winch limit close-in.
- ✓SI ⇄ Imperial toggle converts your inputs in place, so you can work in the units your drawings use
Frequently asked questions
What formula does the capacity at radius — capacity at a radius use?+
It evaluates cap(r) ≈ min(M/r, max line pull), exactly as published. Sources: EN 13001 / EN 14439 — Crane design & tower crane standards; ASME B30.5/B30.9/B30.20 — Cranes, slings and below-the-hook devices. The substituted worked example on the page lets you verify every step against the textbook.
How should I read the result — and how far can I trust it?+
The same arithmetic forward: moment ÷ radius ≈ available capacity, capped by the max-load winch limit close-in. Rigging and crane decisions are life-safety critical. This calculator is a planning aid — the load chart, sling tags, site lift plan and a qualified lift director govern every real lift.
When is this calculator the right tool for the job?+
Approximate available capacity at a working radius from the moment rating, capped by max line pull. A free crane load, wind & rigging safety tool. Real charts step rather than glide because of reeving changes (2-fall to 4-fall); treat this smooth curve as the envelope between chart points, never above them. For neighbouring scenarios, the related tools below cover the same engine with different presets.
Does it support both metric and imperial units?+
Yes — the SI ⇄ Imperial toggle converts the values already in the fields, preserving the physical quantity, so you can flip mid-calculation without re-entering anything.
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