You trying to get a longer cut out of your chainsaw? Or maybe just looking at a replacement bar?

Either way, we’re with you.

There are two main things to look at, when considering if you can put a longer bar on your chainsaw.

Your chainsaw’s engine power
The manufacturer’s manual

There’s also a section below, which explains what other chainsaw components you’ll need to replace when you change out your bar.

We’ll dive into the details below, and in 5-10 minutes, you should have the answers you need. Let’s get to it!

Bar length based on chainsaw power

The biggest thing that affects the compatible length of chainsaw bars, is the engine power of the chainsaw. That’s what we’ll focus on in this section.

If you’d like to learn about pitch, gauge, and other bar measurements (other than length), check out our comprehensive chainsaw bar guide.

Generally speaking, the higher the power of a chainsaw, the longer the guide bar it can handle.

Chainsaw power is measured using the following units:

Displacement (gas chainsaws)
Amps (plug-in electric chainsaws)
Volts (battery chainsaws)

Displacement is measured in cubic centimeters (CC), and is the volume of air that is displaced by the cylinders in the engine.

The other two (amps and volts), you’ve probably heard of before. Though the math can get a bit dense for the precise measurements, these are the two units that are used on the market to compare chainsaw power. Here’s a great resource if you want to understand the math.

See the below table for an overview of the bar lengths that a particular sized engine can typically handle. Keep in mind that this is generalized across different models of chainsaw, so it’s always a good idea to double-check your manufacturer’s recommendations before switching your bar, but more on that later.

Here’s the power-to-bar compatibility chart:

Engine Type	Power Rating	Compatible Bars
Gas	25 – 35 CC	12 – 16 Inches
Gas	35 – 45 CC	12 – 18 Inches
Gas	45 – 60 CC	16 – 20 Inches
Plug-in Electric	8-12 Amps	10 – 16 Inches
Plug-in Electric	13-15 Amps	14 – 18 Inches
Battery	18-20 Volts	10 – 12 Inches
Battery	36-40 Volts	10 – 16 Inches
Battery	54-60 Volts	14 – 16 Inches

Trade-off: Length and power

Another thing to keep in mind, is that as you increase the length of your chainsaw bar, the cutting performance will decrease. So as you move towards the upper end of the bar range, you can expect your chainsaw to cut with a bit less power. It’s a trade-off between the length of the cut, and the power applied to the chain.

As an example, imagine you’ve got a 40 CC gas chainsaw, and you put an 18-inch bar on it.

Compared to a 16-inch bar, the 18-inch bar would obviously have a longer cut length. However, the chain also has more distance to travel away from the engine. So running at 16-inches has less length, but more kick. You get the picture.

Checking manufacturer recommendations is also an important step if you’re changing chainsaw components. See more details below.

Find & use the manual: the easy way

I know, user manuals sound incredibly boring.

Don’t worry, I’ve got an approach that I use to find and auto-search chainsaw user manuals, that should make it relatively painless.

But first, here’s why this is important. No matter how you look at it, chainsaws are dangerous machines. So it’s critical to get the details right, and to use appropriately fitting components.

Safety first.

Using the above chart of compatible bar lengths will give you a great ball-park. But at the end of the day, the best place to confirm the bars you can use on your specific chainsaw, is by checking the manufacturer’s manual.

Here’s what I do whenever I need to check compatible parts for a chainsaw:

1. Google “[chainsaw name] users manual”

For example, for a Stihl MS251 chainsaw, I’d just google “Stihl MS251 users manual”. As of today, the #1 result on Google, is the correct manual directly from Stihl.

2. Use “CTRL + F” to search for bar length

Since I’m looking to see if I can run a longer chainsaw bar, I’d hit the CTRL and F keys on my keyboard at the same time. This will make a text box pop-up (FYI – if you haven’t used this before). Then I type in “bar length”.

3. Find the different recommended chainsaw bars

Using the same example above, I found a list of compatible chainsaw bar sizes on just the second result! It says I can use different guide bars with sizes from 12-18 inches. There it is!

What else to change with the bar?

Before you change your guide bar, you will also want to consider the other chainsaw components this might impact.

Specifically, a new guide bar may mean you also need 2 other components:

New chain
New sprocket

If you increase (or decrease) the length of your bar, you will definitely need a new chain. This is pretty straight forward, if the bar gets longer, you’ll need a longer chain to wrap around it.

In addition, you may need to replace your sprocket. Sometimes you don’t need to, but if the pitch or gauge of your new chain is different, you will need a new sprocket.

Pro tip: whenever you buy a new guide bar, also get 2 chains, and a new sprocket together.

This set of components will wear out at about the same time, so buying it all together will help you keep everything maintained. Plus, if you buy them together, you can make sure they’re all compatible.

Wrap-up

If you find yourself wondering, “can I put a longer bar on my chainsaw?”, then you’re in good company.

This is an age old question that’s been pondered by countless arborists, lumberjacks, and home improvement folks. The good news is, you can find the answer in a few simple steps: