Cat 306 mini excavator: Specs, weight, price & key features

The Cat 306 mini excavator sits in one of the most competitive size classes in the industry — the 6-ton range where versatility, hydraulic power, and lifting stability really matter. Caterpillar introduced the 306 to create a stronger, more capable step-up from the 305.5 without pushing buyers into a larger, more expensive 308-class machine. The result is a compact excavator with impressive digging forces, strong lift performance, and the ability to run a wide range of attachments.

For contractors, rental fleets, municipalities, and owner-operators, the 306 is popular because it balances power and transportability. Below is a full breakdown of the Cat 306’s specs, weight, dig depth, hydraulics, price ranges, CR configuration, and what you can expect when adding one to your fleet.

Cat 306 overview

The Cat 306 CR (Compact Radius) is the most common configuration on today’s market. It features a reduced tail swing for tighter jobsite access, making it well-suited for urban work, road construction, utility installation, landscaping, and general excavation.

Caterpillar engineered the 306 for:

• Higher hydraulic horsepower than previous models
• Better lifting performance relative to its size
• Increased stability for attachments
• Lower operating costs and improved serviceability

This machine also shares commonality with the 307 and 308 families, which helps fleets reduce parts and maintenance complexity.

Cat 306 specs (full breakdown)

Operating weight

• Operating Weight: ≈ 15,821 lb (7,175 kg)
• Note: Weight varies slightly based on configuration, stick length, and attachments.

This weight class puts the 306 right in the middle of the “mini” and “compact” categories, giving it mid-range lifting performance while remaining trailer-friendly with the right hauling setup.

Dimensions and digging capability

• Maximum Dig Depth: ≈ 18 ft 1 in (5.50 m)
• Maximum Vertical Wall Dig Depth: ≈ 13 ft 5 in (4.09 m)
• Operating Width: ≈ 78 in (198 cm)
• Tail Swing (Compact Radius): Tight swing profile ideal for confined urban work.

The 306’s dig depth is a major selling point — deeper than most 5-ton minis and comparable to some heavier 7-ton machines. This is why it’s frequently chosen for utility trenching and foundation prep.

Engine and power

• Engine: Cat C2.4
• Net Power: ≈ 55 hp (42 kW)

Its 55-horsepower engine gives it strong performance for this class, especially when paired with high-flow hydraulics and heavier attachments.

Lifting capacity

Lift capacity is one of the 306’s strengths, especially for utility trenching, pipe work, and job sites where stability matters. Actual lift performance varies by stick length, blade position, and how far the load is from the machine, but the 306 consistently outperforms many excavators in the 6-ton class.

Typical lift capacity at ground level:

• Over Front: ~6,000–7,500 lb depending on stick and blade position
• Over Side: ~2,500–3,200 lb (more limited, as expected)

These numbers outperform many competing 6-ton excavators, and hydraulic stability is one of the key reasons the 306 has become popular in municipal and utility fleets.

Hydraulics and flow

• Max Flow: ~24 gal/min (90 L/min)
• Auxiliary Hydraulics: Standard + optional high-flow
• System Pressure: ~3,600 psi
• Coupler Compatibility: Wide range (manual, hydraulic, quick-coupler friendly)

This hydraulic package allows the 306 to run:

• Augers
• Hydraulic thumbs
• Compactors
• Small breakers
• Brush cutters (with appropriate flow)
• Tiltrotators (on some setups)

Source: VeriTread Specs — Caterpillar 306 CR

Cat 306 attachments and pin size

Here’s what’s most common:

• Bucket Pin Diameter: 45 mm (varies by attachment brand)
• Stick Width: Typically compatible with 6-ton class couplers
• Attachment Families:
  • 24–36” digging buckets
  • Grading buckets
  • Hydraulic thumbs
  • Compaction wheels
  • Auger drives
  • Mulchers/brush cutters on high-flow units

Attachment flexibility is one of the reasons the 306 became a strong replacement for older 305.5 or 307 units.

Cat 306 CR vs Cat 306 Standard

The 306 CR is the primary model sold in North America, designed with a compact radius tail swing for urban productivity and transportability. A standard counterweight option exists in certain markets, but the CR is overwhelmingly more common.

Key differences:

• CR = Compact Radius (reduced tail swing)
• Standard = Conventional Tail Swing (rare in this size class)
• CR version is generally easier to transport and work with on tight job sites
• Specs/hydraulics remain largely identical in comparable configurations

Cat 306 weight: operating, shipping and transport

From a fleet perspective, operating weight directly affects stability, transport planning, and attachment performance. The Cat 306’s weight gives it noticeably better lift performance than many smaller compact excavators.

Key weights:

• Operating Weight: ~15,821 lb
• Minimum shipping weight: Slightly lower depending on attachments and tracks removed
• Trailer Requirements:
  • Typically hauled on a 20–25 ton trailer
  • Can be paired with a properly rated gooseneck for shorter transports

Buyers moving up from a 305.5 often underestimate how much more stable the 306 is due to this weight increase.

Cat 306 price (used market snapshot in USD)

Using recent data from Ritchie Bros., here’s a realistic look at current Cat 306 price trends in USD:

Typical price range:

• Low-hour units: $90,000–$120,000 USD
• Mid-hour units: $70,000–$85,000 USD
• High-hour units: $60,000–$70,000 USD

What affects price:

• Year and hour count
• Stick length
• Blade type
• Hydraulic packages (standard vs. high-flow)
• Thumb included or not
• Condition of undercarriage and tracks

If you’re comparing prices or browsing Cat 306 models for sale, you can check available listings on our site.

Want access to more pricing data? Crate an account today to get used to recently sold items.

Is Cat 306 a good investment?

From a fleet perspective, the Cat 306 has a strong reputation for:

1. High hydraulic power for its size

It runs attachments that many 5-ton excavators struggle with.

2. Strong lifting performance

Especially over the front with the blade down.

3. Trusted support network

Caterpillar’s dealership coverage is a major factor for contractors bidding long-term projects.

4. Resale stability

The 306 has held value well in recent years, even in softer equipment markets.

5. Versatility across job types

Utility installations, trenching, municipal work, landscaping, demolition prep, and general construction all benefit from the 306’s capabilities.

Final thoughts

The Cat 306 mini excavator fills a sweet spot in the compact equipment market. It offers more power and deeper digging capability than traditional 5-ton machines while still being nimble enough for tight job sites. Whether you’re comparing specs, evaluating attachments, or researching used pricing, the 306 consistently stands out for reliability, hydraulic capability, and long-term fleet value.

For current availability, you can explore Cat 306 excavators for sale at rbauction.com.

See also

A farmer’s checklist for preparing equipment for resale