Comparison · Mini excavator

Caterpillar 306 CR vs Kubota KX040-4

The Caterpillar 306 CR is about 58% heavier than the Kubota KX040-4 (6,751 vs 4,265 kg), which usually means more stability and lifting capacity but higher transport weight.

The Caterpillar 306 CR has about 40% more engine power (42 kW (56 hp) vs 30 kW (40 hp)).

Beyond the numbers, compare local dealer support, parts availability and resale value for Caterpillar and Kubota in your region: over the life of a machine they often matter more than small specification differences.

	Caterpillar Caterpillar 306 CR	Kubota Kubota KX040-4
Operating weight	6,751 kg (14,900 lb)	4,265 kg (9,400 lb)
Engine power	42 kW (56 hp)	30 kW (40 hp)
Net power (ISO 9249)	41.7 kW (55.9 hp) at 2,200 rpm	—
Max. dig depth	4.11 m (13 ft 6 in)	—
Max. reach at ground level	6.53 m (21 ft 5 in)	—
Track width	1.98 m (6 ft 6 in)	—
Tail swing	1.35–1.47 m (53–58 in)	—
Engine model	Cat C2.4 Turbo, 2.4 L (148 in³)	Kubota D1803 (3 cylinders, turbo, common rail on Tier 4 versions)
Gross power (ISO 14396)	43.2 kW (57.9 hp)	—
Emissions	US EPA Tier 4 Final / EU Stage V	—
Max. dig height	6.12 m (20 ft 1 in)	—
Max. dump clearance	4.62 m (15 ft 2 in)	—
Vertical wall dig depth	3.17 m (10 ft 5 in)	—
Stick length	1.98 m (6 ft 6 in)	—
Shipping length	5.94 m (19 ft 6 in)	—
Transport height	2.41 m (7 ft 11 in)	—
Cab height	2.54 m (8 ft 4 in)	—
Width over upper house	1.96 m (6 ft 5 in)	—
Rubber track width	400 mm (16 in)	—
Ground pressure	35–39 kPa (5.1–5.7 psi)	31–34 kPa
Gradeability	30°	—
Option weights	Counterweight +250 kg; long stick +44 kg; steel tracks with pads +375 kg; angle blade +102 kg; XTC carriage +64 kg	—
Engine power	—	30.1 kW (40.4 hp) gross / 29.0 kW (38.9 hp) net at 2,200 rpm
Max. digging depth	—	3.42 m (11 ft 3 in)
Max. dumping height	—	3.90 m (12 ft 10 in)
Bucket breakout force	—	32.5–42.4 kN (3,315–4,325 kgf), by version
Width	—	1,700 mm (5 ft 7 in)
Pump capacity	—	92.4 L/min (24.4 US gal/min)
Auxiliary flow	—	AUX1 65 L/min (17.2 US gal/min); AUX2 37 L/min
Arm breakout force	—	18.3 kN (1,865 kgf / 4,110 lbf)
Swing speed	—	9.2 rpm
Max. digging height	—	5.34 m (17 ft 6 in)
Max. vertical digging depth	—	2.26 m (7 ft 5 in)
Max. traction force	—	43.4 kN (4,420 kgf)
Shoe width	—	350 mm (14 in) rubber
Crawler length	—	2,175 mm (7 ft 2 in)
Ground clearance	—	330 mm (13 in)
Length	—	5,085 mm (16 ft 8 in)
Height	—	2,485 mm (8 ft 2 in)
Blade width	—	1,700 mm
Fuel tank	—	64 L (17 US gal)
Hydraulic system / reservoir	—	74 L / 42 L
Strengths	+ 56 hp turbo engine gives "big machine" performance + Over 4 m dig depth and 4.6 m dump clearance — loads trucks easily + XTC (extendable carriage) option for multi-tool work + Under 2 m wide and 2.54 m cab height for easy transport + Strong resale and Cat dealer support	+ Powerful 40 hp engine for a 4-tonne machine + Conventional tail — excellent stability and lifting for its weight + Two auxiliary circuits (65 + 37 L/min) for tilt buckets and thumbs + Large 64 L fuel tank + Very popular — easy to find parts, operators and buyers
Watch-outs	− At ~7 t needs a proper truck-and-trailer − Tail swing up to 1.47 m — not zero-tail − Premium price	− Conventional tail swing needs more room than zero-tail models − Superseded by the KX040-5 for new sales − Heavier — over 3.5 t trailer class in Europe
	Full 306 CR review	Full KX040-4 review

Specifications are typical figures for standard configurations and may be measured differently by each manufacturer (for example net vs gross power). Always confirm with the manufacturer or dealer. Build another comparison.