Caterpillar builds more excavator sizes than any other brand. That is helpful once you know how the numbers work, and confusing before you do. A buyer looking at a CAT 305, a CAT 320 and a CAT 336 is looking at three different machines with different trailers, different fuel bills and different jobs. This cat excavator sizes chart breaks the whole family into weight classes so you can match a machine to your site instead of guessing.
At Shanghai Yonggong Trading Co., Ltd we have exported used Caterpillar excavators for more than 20 years. The size questions we answer every week are almost always the same. How wide is it? Will it fit my trailer? How deep does it dig? The chart below answers those first, then the notes explain what each class actually does on site.
How CAT Model Numbers Match Weight
Caterpillar names most excavators after their approximate operating weight in metric tons. A 320 sits near 20 tons. A 330 sits near 30 tons. A 349 sits near 49 tons. Mini machines follow the same logic with a decimal, so a 303.5 weighs about 3.5 tons and a 307.5 weighs about 7.5 tons.
The rule is close, not exact. Operating weight shifts with track shoe width, counterweight, boom length and cab guarding. A CAT 320 can land anywhere between 20.5 and 22.5 tons depending on how it was ordered. Always confirm the plate weight on the machine before you book transport.
Letters after the number mark the generation. C, D, E and F are older series. GC and Next Gen are newer. A 320D and a 320 GC are the same weight class but different machines inside.
CAT Excavator Sizes Chart by Weight Class
| Class | Models | Operating Weight | Typical Dig Depth | Bucket Capacity | Transport Width |
| Micro | 301.5, 302, 303 | 1.5 – 3.2 t | 2.2 – 2.8 m | 0.03 – 0.09 m³ | 0.99 – 1.5 m |
| Mini | 303.5, 304, 305, 305.5 | 3.5 – 5.7 t | 2.8 – 3.7 m | 0.10 – 0.16 m³ | 1.7 – 2.0 m |
| Compact | 306, 307.5, 308, 309, 310 | 6 – 10 t | 3.9 – 4.7 m | 0.15 – 0.36 m³ | 2.0 – 2.5 m |
| Small | 313, 315, 317, 318 | 13 – 19 t | 5.5 – 6.2 m | 0.5 – 0.9 m³ | 2.5 – 2.8 m |
| Medium | 320, 323, 325, 326 | 20 – 27 t | 6.5 – 7.0 m | 0.9 – 1.4 m³ | 2.8 – 3.0 m |
| Large | 330, 335, 336, 340 | 30 – 40 t | 7.0 – 7.6 m | 1.4 – 2.0 m³ | 3.1 – 3.3 m |
| Heavy | 345, 349, 352, 365 | 45 – 65 t | 7.5 – 8.5 m | 2.0 – 3.4 m³ | 3.4 – 3.6 m |
| Mining | 374, 395 | 74 – 95 t | 8.4 – 9.0 m | 4.0 – 6.0 m³ | 4.0 m + |
Use the chart as a shortlist tool. Once you pick a class, check the exact model sheet, because two machines in the same band can differ by a full meter of reach. Our Caterpillar specs table lists weight, engine power, dig depth, bucket size and transport dimensions side by side for the units we hold in stock.
Mini and Compact Machines from 1.5 to 10 Tons
This group grew fastest over the last decade. Cities got tighter and contractors needed machines that fit through gates and between houses.
The 301.5 and 302 are narrow enough to pass a standard doorway. Retractable undercarriages let the tracks pull in for the trip, then spread out for stability during digging. Work here is drain lines, sprinkler trenches, footing prep, tree removal and small demolition inside buildings.
From 306 up to 310 you get a real machine in a small package. Blade options, thumb attachments and hydraulic breakers all become practical. An eight ton class unit such as the CAT 308 handles driveways, gravel work, utility trenches and residential foundations without tearing up the lawn. Cost of ownership stays low and one three axle trailer moves the machine legally in most regions.
Watch the counterweight on this class. Zero tail swing versions protect walls and traffic but trade a little lift capacity for that clearance.
Small and Medium Machines from 13 to 30 Tons
Most earthmoving happens in this band. The 20 ton class is the workhorse of the industry worldwide, which is why the CAT 320 specifications get searched more than any other model.
A 313 or 315 suits road maintenance, pipe laying and site clearing on medium plots. A 320 or 323 digs basements, cuts main water lines, loads trucks steadily and still fits a standard lowboy. Fuel burn sits around 12 to 18 liters per hour depending on work mode.
Boom choice matters more than weight in this class. A standard boom with a short stick gives more breakout force for rock and hardpan. A long reach front end trades force for distance and helps on canal banks and pond work. A two piece articulating boom folds tighter, which helps on narrow city streets.
Bucket sizing follows soil density. In clay a 20 ton machine handles a 1.0 m³ bucket comfortably. In wet sand or shot rock, drop to 0.8 m³ so hydraulic pressure stays in range and cycle times stay short.
Large Machines Above 30 Tons
Production volume drives the choice here. A 30 ton machine moves roughly twice the material per hour of a 20 ton machine when the truck fleet keeps up.
The 330 class serves quarry loading, bulk cut and fill, and heavy demolition. Older units are still common on the secondhand market, so the CAT 330D specs remain a frequent reference for buyers comparing price against hours. Step up to the 336 and you gain reach, lift and a heavier undercarriage for rough ground. Buyers comparing that step usually start with the CAT 336 specifications before committing.
Above 40 tons, transport turns into a project. Counterweights come off. Booms travel separately. Some regions require permits, escorts and night moves. Factor that cost into every job estimate, because a machine that sits waiting for a permit earns nothing.
High flow auxiliary hydraulics come standard on most large models. That matters if you plan to run heavy breakers, shears or pulverizers.
Transport Width and Trailer Limits
Weight class decides the trailer. Check three numbers before you buy any machine.
Transport width tells you whether you need an oversize permit. Many regions allow 2.5 to 2.6 m without paperwork. A 320 at 2.9 m already needs a permit in those places.
Transport height matters for bridges and tunnels. Cab guards and folded booms add more than people expect.
Combined weight of tractor, trailer and machine sets your axle load. A 36 ton excavator on a three axle lowboy will exceed limits in most countries. Plan for four or five axles.
Older CAT Models on the Used Market
Buyers searching a caterpillar excavator sizes chart often land on models Caterpillar no longer builds. Those machines still work well and cost far less.
The 305.5E and 306E cover mini work at a fraction of new pricing. The 312D and 313C fill the small class. The 320C and 320D remain the most traded excavators on earth, with parts available in every market. The 329D, 330D and 336D handle heavy production work at prices well below current Next Gen units.
Age changes what to inspect, not what the machine can do. Look at undercarriage wear, pin play in the boom and stick, hydraulic cylinder seals, and service records. A 2018 machine with 3,000 hours and clean maintenance history usually outperforms a 2022 machine that was run hard and neglected.
Which CAT Size Fits Your Job
Match the machine to the tightest constraint on your site, not the biggest task.
Pick mini or compact if access is narrow, surfaces need protection, or you work inside residential areas. Pick 13 to 19 tons for utility work, road repair and medium foundations. Pick 20 to 27 tons for general construction where one machine must cover most tasks. Pick 30 tons and up when hourly production drives your income and you have trucks to match.
Then check the trailer, the fuel budget and the operator. A machine one size too big costs money every hour it runs. A machine one size too small costs money every hour it struggles.
