"What size excavator do I need?" is the first — and most expensive — question to get right when buying a digger. Choose too small and you'll spend extra hours on every job; choose too big and you'll burn fuel, transport budget and capital you didn't need to. Excavators in Australia run from 1-tonne micro machines that fit through a garden gate to 40-tonne-plus production units that rarely leave a mine site.
This guide breaks down every size class in plain English — what each one is built for, how deep it digs, what it costs, and how to transport it — so you can match the machine to your work with confidence. Wherever a size fits, we link straight to live listings so you can see what's on the market today.
Excavator size classes at a glance
Excavators are grouped by operating weight. The industry loosely splits them into mini (up to ~6 tonne), midi (6-10 tonne), and full-size (10 tonne and up). Here's the quick reference:
- 1.5 tonne (micro): ~1,500-2,500kg · dig depth 2.0-2.5m · confined-space and landscaping
- 3 tonne (mini): ~2,500-4,000kg · dig depth 2.8-3.2m · the all-rounder
- 5 tonne (mini): ~4,000-6,500kg · dig depth 3.6-4.2m · mixed residential and light commercial
- 8 tonne (midi): ~6,500-10,000kg · dig depth 4.2-5.0m · first truly commercial size
- 13 tonne: ~10,000-16,000kg · dig depth 5.5-6.5m · commercial civil workhorse
- 20 tonne: ~16,000-25,000kg · dig depth 6.5-7.5m · bulk earthworks and mine support
- 30 tonne: ~25,000-35,000kg · dig depth 7-8m · heavy civil and quarrying
- 40 tonne+: 35,000kg and up · mining and major infrastructure
1-1.5 tonne: micro excavators
The smallest tracked excavators on the market, micro machines are built for work where nothing bigger will fit — backyard landscaping, fence lines, narrow-access trenches, pool digs and interior demolition. Most 1.5 tonne units pass through a standard 900mm gate with the tracks retracted and can be trailered behind a mid-size ute without a special licence. Despite the size, modern units offer near-zero tail swing, rubber tracks that protect finished surfaces, and quick-hitch compatibility with buckets, augers and breakers. Expect used pricing of roughly $15,000-$35,000.
Browse 1.5 tonne excavators for sale to see current listings.
2-3 tonne: the all-rounder
The 3 tonne class is the most popular size in Australia, and for good reason: it's the sweet spot between the confined-space micro and the larger 5-tonne mini. With dig depths of 2.8-3.2 metres and enough breakout force for real civil work, a 3 tonne machine still trailers easily, passes through most residential access, and runs on rubber tracks without tearing up lawns. Popular models include the Kubota U35, Yanmar VIO35, Bobcat E35 and Takeuchi TB235. If you can only own one excavator, this is usually the right call. Used pricing typically runs $25,000-$55,000.
See 3 tonne excavators for sale.
5 tonne: residential meets light commercial
5 tonne machines are the largest of the "mini" class and the smallest that feel genuinely capable on a commercial civil site. With 3.6-4.2 metre dig depth and the hydraulic power to run a full set of attachments, a 5 tonne unit will dig a pool, trench a driveway's worth of drainage and lift reasonable-diameter pipe. Most still fit on a standard 3.5-tonne plant trailer, though you're approaching the limit. Budget $40,000-$85,000 used.
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8 tonne: the first truly commercial size
Often called midi excavators, 8 tonne machines step up into genuine civil capability — heavier undercarriages, more comfortable cabs, and hydraulic flow high enough for full-size breakers and tilt hitches. Dig depths of 4.2-5 metres and the muscle to rip compacted clay make this the workhorse for bulk trenching and building-pad prep. Transport requirements jump here: you'll need a purpose-built plant trailer behind a heavy rigid or light prime mover. Used pricing runs $60,000-$140,000.
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13 tonne: the commercial civil workhorse
The most popular mid-size class in Australia. With 5.5-6.5 metre dig depths and bucket capacities around 0.5-0.7 cubic metres, the 13 tonne class is the standard choice for bulk trench work, stormwater infrastructure, road construction and subdivision earthworks. These machines need a dedicated float or plant truck to move, not a drag-on trailer. Expect $80,000-$180,000 used depending on hours and attachments.
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20 tonne: bulk earthworks and mine support
The most common large-class excavator in Australian construction and mining support. With 6.5-7.5 metre dig depth and 0.9-1.3 cubic-metre buckets, a 20 tonne machine has the productivity to keep a rotation of trucks moving on bulk earthworks, quarry loading and demolition. All require float transport. Used pricing ranges $90,000-$250,000, and low-hour Japanese and European brands hold value exceptionally well.
See 20 tonne excavators for sale.
30 tonne and 40 tonne+: production machines
The 30 tonne class is a large production machine for heavy civil, major quarry operations and mine support, with 7-8 metre dig depths and buckets up to 2 cubic metres. Above 35 tonnes you're into dedicated mining and major-infrastructure territory, where machines are purpose-selected for site conditions and new pricing starts around $600,000. These units rarely leave site and need heavy float transport when they do.
Browse 30 tonne excavators for sale or 40 tonne-plus excavators for sale.
How to choose the right size
Work through four questions in order: access (the tightest point the machine must reach), dig depth (how deep your typical job goes), transport (can you tow it, or do you need a float), and productivity (how much material you move per day). The right machine is the smallest one that comfortably clears all four. When you're genuinely between two sizes, the 3 tonne and 13 tonne classes are the safest defaults — they're the most traded, so you'll find more choice, better pricing and stronger resale.
Financing your excavator
Excavator finance is straightforward to arrange and lets you preserve working capital rather than tying it up in a single machine. Repayments scale with the purchase price, so knowing your finance number up front keeps you shopping in the right size bracket. You can get a fast, no-obligation quote through excavator finance with Equifund — most applications are answered within 24 hours.
Ready to compare machines? Browse every excavator for sale from trusted Australian dealers on Asset Scanner, filter by size and state, and line up finance from the listing.