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How to Measure a Chainsaw Bar – 2 Effective Methods

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A chainsaw is a mechanical cutting device used for various purposes such as limbing, pruning, felling, cutting firewood, and so much more. A chainsaw is a portable tool usually powered by battery, gasoline, or electricity.

A chainsaw consists of a cutting chain and a bar around which the chain rotates. This bar supports and holds the chain and is an essential component of the chainsaw.

With all the heavy-duty work, the teeth and the chainsaw bar may wear down, and you will need to replace them.

It is extremely important to know what size of bar you need for your chainsaw because using a bar with the wrong size may cause your chainsaw to malfunction or break down. It may also cause injury to the person operating it.

Choosing the right-sized bar for your chainsaw is essential to keep it running smoothly and avoid injuries. In this article, we will teach you different methods of how to measure a chainsaw bar.

When Do You Need to Change Your Chainsaw Bar?

If you cannot figure out when exactly your chainsaw bar needs to be changed, follow this guide. Look for the signs which might indicate that it is time to change your chainsaw bar.

  1. If the bar is damaged or bent
  2. Visible cracks or fractures on the bar rail
  3. Pinched or narrowed rails and grooves
  4. The chain keeps wiggling or sliding from the bar
  5. If the blades of your chain are tilted or angled
  6. The nose sprocket of the bar shows signs of damage or is jammed

Why is it Important to Change the Chainsaw Bar?

It would help if you never overlooked a damaged or deteriorating chainsaw bar. The chainsaw bar is one of the main components of the chainsaw, and it is crucial to keep the chainsaw working smoothly.

A damaged chainsaw bar can essentially decrease the efficiency and effectiveness of the working of the chainsaw. Not only that, it can pose a serious threat of injuries to the operator. If your bar is damaged, it may even cause the chainsaw to stop working altogether.

To keep your chainsaw working smooth, make sure that the bar and chain are in good condition.

Size-Guide for Buying a Chainsaw Bar

Buying a right-sized bar is very important. You can’t just use any size of bar with any chainsaw. You will need to buy a bigger sized bar for a powerful saw and vice versa.

Chainsaws usually come in even-numbered sizes. A longer bar is more appropriate for a powerful chainsaw because it needs more energy to power the chain around it.

A chainsaw bar and the chain complement each other, and they have to be in perfect synchronization for the chainsaw to operate properly.

All of this information about the right size of the chainsaw bar and chain is given in the instruction manual of your chainsaw. But it’s been a while since you bought the chainsaw, and that instruction manual is long lost?

In that case, we are here to help you. We will teach you how to measure a chainsaw bar with our step-by-step instructions.

2 Methods on How to Measure a Chainsaw Bar

After learning all the basics and why changing a chainsaw bar is important, let us now teach you how to measure a chainsaw bar. And for your further assistance, we have added a link to a video tutorial on how to measure a chainsaw bar.

You can measure your chainsaw by using the following two methods.

Method 1: Measuring the Effective Cutting Length

You can measure the length of your chainsaw using a measuring tape with the following method. This method is more common and much easier.

  1. Take a measuring tape.
  2. Measure the length of the bar from the tip of the bar to the endpoint where the bar is entering the chainsaw.
  3. Note down your measurement and round it off to the nearest even number.
  4. As mentioned earlier, chainsaws are only sold in even number sizes, so if the effective cutting length of your bar comes out around 11″, then it is a 12″ chainsaw, and if the effective length is 18-1/2, then it is a 20-inch chainsaw.

Method 2: True Length of the Bar

The second method to measure a chainsaw bar is measuring its true length. This method is quite uncommon, but it gives more accurate and precise results. Follow these steps to measure the true bar length of your chainsaw.

  1. Unscrew the bolt of the chainsaw where the bar is attached and gently take out the bar.
  2. Place the bar on a flat surface.
  3. Take a measuring tape and ensure the length of the bar from one end to the other.
  4. Since this method involves measuring the bar precisely from one end to the other. Therefore, you don’t need to round off your measurement.

How to Change a Chainsaw Bar?

Now that you’ve learned how to measure a chainsaw bar, it’s time for you to know how to change it as well. Follow these simple steps to change your chainsaw bar.

  1. After measuring and buying the right size of bar for your chainsaw, it’s time to replace it.
  2. First things first, gear up! Wear some heavy-duty gloves and keep the face of the bar away from yourself.
  3. Make sure that the power is turned off before replacing the bar.
  4. If your chainsaw is covered, then remove the cover. You will see two nuts attaching the bar to the chainsaw’s body. Unscrew these nuts to remove the sprocket cover.
  5. Once you have removed the nuts, take off the clutch cover and put it aside.
  6. Now remove the bar from the chainsaw’s body.
  7. Before you remove the bar, please give it a gentle push backward to reduce the tension from the chain. You can easily remove the loosened bar and chain by sliding it from adjustment posts.
  8. After removing the bar, clean the area inside the sprocket and lubricate it.
  9. Now take the new bar and slide it onto the adjustment posts. Now you can reinstall the chain on the bar. Adjust the chain properly in the grooves and rails of the bar.
  10. While installing the chain on the bar, remember that the sharp teeth should be facing forward towards the bar’s tip.
  11. Pull the bar in the forward direction to create the tension in the chain and tighten the chain as required.
  12. Once the chain is tightened, place the sprocket cover back in its place.
  13. Take the sprocket cover nuts and tighten them.
  14. While tightening the nuts back, make sure that you screw them properly and check to ensure they are not loose.


Like any other tools, chainsaws are prone to wear and tear after using for some time. To ensure your chainsaw runs smoothly and effectively for a long period, it needs proper maintenance.

Changing and measuring a chainsaw bar is a menial task that you can easily do on your own without any professional assistance. To help you with how to measure a chainsaw bar, we have enlisted two methods. Please leave your feedback in the comments on how it worked out for you!