What Size Chainsaw Do I Need? [Bar Length + Weight]

Photo of author
Written By Michael Culligan

With over 12 years of experience in Oregon's forestry industry, I have established myself as a skilled and knowledgeable lumber professional. As a passionate competitor in local timbersports events, I have consistently ranked among the top lumberjacks in my area. I take great pride in meticulously maintaining an extensive collection of restored vintage axes. I personally test every axe I review by using it to fell and chop up oak firewood on my land.

REVIEWED BY SPencer Durrant
As an Amazon Associate I earn from qualifying purchases.

As a homeowner, choose a chainsaw with a 16-20 inch bar length for optimal versatility, suited for trimming, pruning, and cutting small-to-medium-sized trees. Gas-powered chainsaws offer more power, while electric and battery-operated options provide ease of use and lower maintenance.

One of the first questions a beginner chainsaw user always asks is “what size chainsaw do I need?” This truly depends on the specific tasks you will be cutting.

My quick summary is this:

  • Landscapers or gardeners mostly likely need a chainsaw with a 10 to 14-inch bar length.
  • Landowners who intend to cut through smaller logs/trees should get a 16 to 18-inch bar length, but if you intend to cut through larger trees then could go up to a 20 to 24-inch bar chainsaw.
  • Industrial or professional chainsaw operators in sawmills and forestry workers can use chainsaws over 24 inches in bar length.

There are so many different types and sizes of chainsaws it can be difficult to really narrow down to that tool that suits your needs. To help out, I have compiled more comprehensive answers based on my experience working with chainsaws over the last decade.

What Size Chainsaw Do I Need

How to Choose the Right Sized Chainsaw

I have bought many chainsaws over the years and have developed a quick system to help pick the exact model you need.

Step 1 – Understand your Requirements

There are two mistakes I often see when people are buying their first chainsaw – picking a model that is too small for the sized wood they intend to cut and selecting a model that is ridiculously large for the smaller, delicate tasks. It is essential to understand your actual requirements:

  • Go for a walk around your property – what is the size of the largest tree/log that you are likely to cut. Use a tape measure to check their diameter for accuracy.
  • How often will you be using your chainsaw – is it cutting a single log once a month or processing multiple trees into firewood for a week straight.
  • What is your physical strength – chainsaws can be very heavy and put a lot of strain on your muscles. So be honest with yourself and don’t get a tool that you can’t use.

Step 2 – Choose the Bar Length

This guide bar length you require is defined by the maximum sized log or tree you need to cut. The largest log I would ever cut would be 2 inches shorter than the bar length. This allows you to put one edge of the log against the bumper spikes, and gives you 2 inches of safety margin to avoid the kickback zone around the chainsaw’s nose.

If you are inexperienced with chainsaws, then you should give yourself an additional safety margin for the largest logs.

If you have a lot of different-sized logs to cut, then it might be worth picking two chainsaws with bar lengths that are better suited for their specific task.

Step 3 – Pick the Engine Type

The next decision is whether to pick a gas or electric-powered chainsaw. Electric chainsaws have made big leaps in design and performance to the point where they are viable alternatives for recreational users.

Gas chainsaws are generally more powerful and can cut longer between refuelling. They can be more difficult to start when you start needing to mess around with chokes and pull starts. They are also much heavier than electric chainsaws.

Electric chainsaws are easier to start, and don’t require refuelling, but you will need secondary batteries if you don’t want to wait a few hours between cuts.

Step 4 – Select the Brand

Picking a reputable manufacturer is the last step. I have particular chainsaw brands that I have faith in, and there are some that I would never use. The differences are around the design, the availability of spare parts, the warranty, and the construction quality/materials.

I believe that getting the best value for money chainsaws is more about selecting a machine that will work for the next decade rather than selecting a cheaper price with a risk of failing after two or three years.

You can find chainsaw comparison charts, like this one from Stihl, that help to break down their products into recommended uses such as pruning, storm cleanup, and cutting firewood.

How to Measure Chainsaw Size

The length of their guide bar defines the size of the chainsaw. This is used as a comparison measure to help understand the effective cutting length of the chainsaw. My rule of thumb is that a chainsaw can cut logs that are 2 inches shorter than their bar length. This means that a 20-inch chainsaw can cut through an 18-inch log at the absolute extreme. The 2-inches gives you some margin to keep the cutting below the nose and the kickback zone.

If you are not experienced with a chainsaw, you should start with a smaller tool and work your way up as you gain experience and tackle more significant tasks.

Another point to note, is that the weight of the chainsaw can vary significantly for the same size bar. For example, the ECHO 18-inch gas Chainsaw weighs 12.1 pounds, compared to the Makita Rifgeline 18-inch gas chainsaw at 19.4 lb. If you expect the weight of the chainsaw as part of the size, then keep this in mind. The size of the fuel tank, the engine, and the material of construction all play a role in the total weight of the machine.

You should seriously consider your own strength and health before buying a heavy chainsaw. They can really fatigue your muscles quickly.

Chainsaw Sizes for Specific Tasks

One of the simplest ways to narrow down the chainsaw size you need is based on the individual tasks you will be tackling. I have split this into the most common jobs a landowner will use their chainsaw to complete.


Landscapers generally require the smallest chainsaws, in the 6 to 10-inch bar length range. This is generally for timing branches, felling small trees, and general yard work.

Pruning Trees

Pruning trees is another chainsaw use that focuses on the smaller end of the product range. This is really based on the size of the trees and could be anything from 6 to 10-inch bar length.

Limbing Branches

Limbing branches can be a wide range in chainsaw size requirements and could be anywhere from 6-inch for smaller tree branches up to 14-inch for larger oaks.

Cutting Firewood

Cutting firewood is probably the most common task that most landowners will use their chainsaw for. You can use the rule of thumb here to get a chainsaw that is 2 inches longer than the largest log you will cut. You should also consider the quantity of firewood you are going to cut. If you are going to process an entire winter’s worth of firewood over the next week, then I would get a slightly larger chainsaw to get through the job more quickly. If you are only going to cut through a days worth of firewood every morning, then a smaller chainsaw can be sufficient.

I would pick a 14 to 18-inch bar chainsaw for cutting firewood, depending on the diameter of the logs.

the ideal sized chainsaw for cutting logs
This is an example of the ideal-sized chainsaw to cut through this log with enough length away from the nose.

Felling Trees

Last on my list of common chainsaw tasks is felling trees. For this task, you will likely want a chainsaw from 16 to 20-inches in bar length. You should also consider the engine size based on the wood hardness. Cutting through hardwood will require a more powerful chainsaw than softwood (or it will just take a lot longer).

My key takeaway from felling many trees well (and a few trees poorly) is to ensure your chainsaw is large enough to cut through the tree in one pass. There are few things as dangerous as a tree that is half cut while you are walking around it to reposition for a second cut.

How Big a Tree Can a Chainsaw Cut?

A chainsaw can cut through a tree or log that is at least 2 inches shorter than the bar length.
A 20-inch bar chainsaw can cut through an 18-inch diameter log.
A 16-inch bar chainsaw can cut through a 14-inch diameter tree.
A 10-inch bar chainsaw can cut through 8-inch branches.
This rule means giving yourself a two-inch gap between the chainsaw’s effective cutting length and the kickback zone.


Picking your first chainsaw (or even your tenth) comes with a lot of questions that need to be answered: what sizes logs will I be cutting, how hard is the wood, how large an engine do I need, and how heavy a tool can I lift? Understanding your own requirements is the first step to making sure you don’t make a buying mistake. Then use my rule of thumb to narrow your selection to a particular bar length. If you are looking to do multiple jobs, it may be worth getting two different chainsaws that are both ideally suited to their own tasks.