Free Tool — Crane
Crane Load Ratio Calculator
Compare a known load and below-the-hook rigging weight with capacity you enter from the exact manufacturer chart for the crane, configuration, and radius. This study tool does not select a chart or approve a lift.
Crane Load Ratio Calculator
From the exact chart for this crane, configuration, and radius
All below-the-hook gear not already included in load weight
Other deductions required by the selected chart; do not double-count rigging
Entered Capacity Utilization
38.8%
Within the entered net chart capacity — not a lift approval.
Total Load
15,500 lbs
Net Capacity
40,000 lbs
Entered Capacity Remaining
24,500 lbs
Calculation boundary
Gross load = object weight + below-the-hook rigging weight
Entered net capacity = chart capacity − other chart-required deductions
Utilization = gross load ÷ entered net capacity × 100
No universal 75%, 85%, or 90% safe zone is applied.
For exam practice and estimation only — not a substitute for engineered design, manufacturer data, current codes, or a licensed professional's judgment. Verify all values before relying on them.
What this calculator can verify
This page performs one arithmetic check: gross entered load divided by entered net chart capacity. OSHA requires the operator to follow manufacturer procedures and keep the applicable load chart and warnings available in the cab. The equipment must not be operated above its rated capacity.
The current CCO Mobile Crane Operator candidate handbook lists load charts as a Core domain. It expects candidates to choose the chart for the machine and application, use the rated-capacity, range, work-area, and parts-of-line information, and distinguish what the chart's capacity rating includes.
A percentage from this calculator cannot establish that the chosen chart, radius, boom length, work area, counterweight, outrigger or crawler setup, parts of line, ground conditions, weather, and chart-specific deductions are correct. Verify those inputs against the manufacturer's procedures before relying on any calculation.
Frequently Asked Questions
What crane load ratio does OSHA consider safe?
OSHA 1926.1417 does not create a universal 75%, 85%, or 90% safe operating zone for ordinary lifts. It requires compliance with manufacturer procedures and prohibits operation above rated capacity. The 75% figure in 1926.1417(o)(3)(ii) is a trigger in one method for verifying an otherwise unknown load weight; it is not a general lift-approval threshold.
What weight should be included in a crane load calculation?
Use a load weight determined by a recognized source or calculation method, then account for the rigging and other equipment that imposes load. The exact manufacturer chart controls what its capacity rating already includes and which deductions apply. Do not enter the same hook, block, sling, attachment, or other item in both fields.
How does boom radius affect crane capacity?
Use the manufacturer's chart for the exact radius, boom length, work area, and crane configuration. This calculator does not infer a capacity from radius and must not be used to interpolate or extrapolate chart values.
Does the CCO Mobile Crane Operator Core exam include load charts?
Yes. The current CCO candidate handbook lists Load Charts as a Core domain and names rated-capacity charts, range diagrams, work-area charts, parts-of-line information, and chart limitations. VoltExam is independent supplemental practice and is not affiliated with or endorsed by CCO.
Also try: OSHA Fall Clearance Calculator
Total fall clearance distance per OSHA 1926.502 — pass/fail by anchor height
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Practice 5 Crane / NCCCO exam questions
Supplemental practice questions — each with an explanation.
Crane / NCCCO · Question 1 of 5
What is the definition of 'Gross Capacity' as listed in a crane's load chart?
Pick an answer to see the explanation + an instant AI breakdown.