What Size Chainsaw Do You Need?
"Size" on a chainsaw means two related things: the guide-bar length (how thick a piece you can cut in one pass) and the powerhead's output (how easily it pulls a chain through wood). Matching both to your task is the goal. The figures below are general guidance, not hard rules — always defer to the manufacturer's recommended bar range for a given saw.
How bar length relates to cut size
A guide bar can cut wood up to roughly its usable length in a single pass; thicker wood requires cutting from multiple sides. A longer bar adds reach but also weight, and it needs enough power to drive the extra chain without bogging down.
By task
- Pruning and light limbing: short bars, often around 10–14 in, on light saws (compact battery or small gas). Easy to handle for overhead and one-handed-rated work.
- General property work and firewood: mid-length bars, roughly 16–18 in, on mid-size powerheads — a common all-rounder range.
- Felling and bucking larger trees: longer bars, about 18–24 in, paired with higher-displacement gas engines for sustained cutting.
- Milling lumber: the longest bars and the highest displacement available, because the saw runs buried in the cut for long passes.
Power: displacement, watts, and weight
On gas saws, engine displacement (cc) is the usual power proxy: higher displacement supports longer bars and harder use. On battery and corded saws, motor power (watts) and battery voltage play a similar role.
Weight matters too. A lighter saw fatigues you less over a long day, which is why power-to-weight is a useful lens for demanding work — we publish weight on every model.
Related on SawFacts
Find models sized for your task:
- Chainsaws for firewood
- Chainsaws for felling trees
- 20-inch chainsaws
- Chainsaws for milling
- Lightweight chainsaws
- Gas chainsaws
Frequently asked questions
What size chainsaw do I need for firewood?
For general firewood cutting, a mid-size saw with roughly a 16–18 in bar is a common all-rounder choice; larger logs or heavier use favor an 18–20 in bar on a higher-displacement powerhead. Match the bar to the diameter of wood you cut most often.
What size bar do I need to fell a tree?
As a rule of thumb, a bar a few inches longer than the trunk diameter lets you complete felling cuts more easily; for larger trunks, an 18–24 in bar on a higher-displacement gas saw is typical. Felling is hazardous — seek training and follow safe felling practice.
Can a small chainsaw cut a big tree?
It can, by cutting from multiple sides, but an undersized saw works slowly and is harder on both the operator and the tool. Matching bar length and power to the wood is safer and more efficient.