Chainsaw Buying Guide: Bar Length, Engine Size and Picking the Right Saw

With dozens of chainsaw models on the market, the spec sheet alone doesn't tell you much. What actually matters is matching engine size and bar length to the job you're doing — here's how to work that out, plus answers to the questions we hear most often.

Start with the job, not the engine size

A chainsaw that's too big is tiring to handle and overkill for small jobs; one that's too small will bog down in anything thicker than a fence post. As a rough guide: pruning and light branch work suits a 30–40cc saw with a 14–16" bar, routine firewood cutting suits a 40–50cc saw with a 16–18" bar, and felling larger trees or heavy property clearing calls for a 50cc-plus saw with an 18–24" bar.

Chain pitch and gauge, in plain terms

Chain "pitch" is the distance between the drive links, and "gauge" is the thickness of the part that sits in the bar's groove. You don't need to memorise the numbers — the bar and chain that come with a new saw are already matched. When you replace a chain later, match the pitch, gauge and drive link count exactly, rather than just going by bar length.

Frequently asked questions

What size chainsaw do I need for cutting firewood?

For most household firewood — cutting rounds from timber that's already down, rather than felling it yourself — a 40–50cc petrol saw with a 16–18" bar handles the job comfortably without being heavy to swing for a full session.

What's the best chainsaw for gum trees or hardwood?

Hardwood like gum takes more power to get through cleanly, so it's worth stepping up a size from what you'd use on softwood. A saw like our 65cc petrol chainsaw with a 24" bar suits regular hardwood work; go smaller if it's only occasional.

Do I need a licence to use a chainsaw in Australia?

No general licence is required for personal or property use, though some states require a ticket for commercial tree-felling work. Always check your state's work health and safety regulator before using a chainsaw for paid work — see Safe Work Australia for general guidance.

How long should a chain last before it needs sharpening?

That depends on use, but as a rule of thumb: if the sawdust coming out looks like powder rather than chips, or the saw starts pulling to one side, it's time to sharpen. Regular light touch-ups with a file every few tanks of fuel keep a chain cutting cleanly for much longer than waiting until it's fully blunt.

Is a longer bar always better?

No — a longer bar adds weight and reach you may not need, and makes the saw harder to control for detailed work. Match bar length to the largest diameter you're regularly cutting, with a little headroom, rather than the biggest branch you might occasionally face.

Once you've settled on the type and size, our Chainsaws range covers everything from light-duty electric models to commercial-rated petrol saws. If you're still weighing up power types, we've compared that in detail in Electric vs Petrol Chainsaws, and once you've got a saw, our chainsaw storage and maintenance guide covers keeping it reliable between jobs.