How to Measure Chainsaw Bar

| Last Updated: February 8, 2021

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A lot of people seem nervous about measuring the chainsaw bar as they tend to overcomplicate the task.

It’s easy and relatively straightforward. 

All you need is a measuring tape, a wrench, and your chainsaw. 

How Do You Measure a Chainsaw Bar? - TL;DR (Too Long; Didn’t Read)

Before we get too far, here's a quick summary of how to measure a chainsaw bar:

  1. Disengage the spark plug and any power sources
  2. The effective cutting length - You measure from the nose to the last part of the bar that’s exposed.
  3. The full length - Remove the bar from the chainsaw and measure the entire bar. 

Chainsaw Bar Terminology

Chainsaw users are bombarded with terminology to quickly pick up; below are some terms you’ll encounter when working with your chainsaw bar

  • Guide Bar - The actual bar itself tends to be made from a steel laminate or durable alloy. The chain will wrap around this bar. 

  • Effective Cutting Length - The length of the bar that is exposed enough to make a cut. Anything from the nose to the point at which it disappears into the chainsaw body can be regarded as the effective cutting length.

  • Full Length - This is the bar's entire body; this is measured from tip to tip. 

  • Spark Plug - The spark plug provides the chainsaw power, so this is usually removed when measuring the bar or cleaning it. 

How Do You Measure a Chainsaw Bar?

Now we’re going to walk you through how to measure your chainsaw bar correctly. 

Remove The Power

This can be done by taking the power cable out and turning the spark plug off. This is just a precaution to ensure the bar is safe to handle. 

Measure The Effective Cutting Length

You can simply take your measuring tape and measure from the tip of the nose down to the exact point that it is no longer exposed. This often isn’t a round number; it’s acceptable just to round this number up. 

Measure The Full Bar Length

You firstly have to remove the bolts that hold the casing and bar together. They can be removed using a wrench. You place the bar on a flat surface and then measure from one end to the other, and that’s the full bar length. 

Chainsaw Bar Length vs. CC 

Bar length is probably more important as you would require specific lengths to cut trees of varying thickness. For example, you can’t cut a 28” thick tree with a 12” inch long bar; that just wouldn’t work.

You can use a 50cc engine along with a 30” long bar, the engine won’t be as powerful, and the task will take longer, but it can still be used. 

The higher the CC, the more power you get; a low powered engine with a long bar can be worked around. But a small bar with a powerful engine can’t be worked with. 

Chainsaw Bar Length vs. Tree Diameter 

The length of your bar must be at least two inches longer than the diameter of the tree you’re cutting. For example, if you’re cutting a tree with a thickness of 12”, you’d require a bar length of 14” to properly cut down the tree. 


Measuring your chainsaw bar is a lot more straightforward than most people realize and can be done in less than 10 minutes. Today's key takeaway is that to trust your gut and doesn’t overcomplicate things because they seem complicated, just use common sense.