A mobile crane is a self-propelled lifting machine built for controlled vertical and lateral movement of heavy loads. It combines a carrier frame, an upper structure, a boom or lattice mast, hoisting gear, outriggers or stabilisers, and control systems. Lifting capacity on any mobile crane is governed by load charts tied to boom configuration and working radius, with hydraulic and electronic controls improving precision and safety.

Classification of mobile cranes is based on carrier type, boom configuration, lifting capacity and intended application. The main categories are: truck-mounted cranes offering fast road mobility and moderate lift capacity for urban and road-adjacent tasks; all-terrain cranes combining highway speed with off-road capability through off-road suspension and multi-axle steering; rough-terrain cranes featuring a single-unit chassis on large tyres with high ground clearance for confined, uneven sites; crawler cranes using track-mounted systems to deliver superior ground contact, low ground pressure and high stability; carry-deck cranes as compact, deck-mounted units for plant maintenance; and boom trucks with telescopic booms on truck chassis for rapid deployment.

Wheeled mobile cranes — truck-mounted, all-terrain and rough-terrain types — drive to site and extend outriggers that press down on mats or pads to create a fixed lifting footprint. Crawler cranes use tracks that spread weight across a larger contact area, lowering ground-bearing pressure and allowing the crane to lift without outriggers. Crawler cranes require extensive on-site assembly and are not road-legal, travelling between sites on low-loaders rather than under their own power.

A telescopic boom extends and retracts hydraulically for fast reach adjustment and quicker rigging. Lattice booms, assembled from truss sections on site, lift heavier capacities at greater heights and further distances but take longer to set up. Boom material choice balances strength, weight, fatigue life and transport dimensions, while hybrid boom designs aim to combine the reach of telescopic systems with the capacity of lattice construction.