April 14, 2026 JUN

How to Measure a Chainsaw Bar Correctly

If you are replacing a chainsaw chain or guide bar, one of the first things you need to know is your bar size.

That sounds simple, but many people measure the entire metal bar from end to end and get the wrong number.

In most cases, the number used for replacement parts is the cutting length, also called the called length, not the total overall length of the guide bar.

In this guide, you will learn how to measure a chainsaw bar correctly, what bar length actually means, and how to use that information to choose the right replacement chain or bar.

Quick Answer

To measure a chainsaw bar correctly, measure from the front edge of the chainsaw body to the tip of the guide bar.

Do not measure the section hidden inside the saw housing.

Then round the measurement to the nearest standard inch size, such as 14", 16", 18", or 20".

Why Measuring a Chainsaw Bar Correctly Matters

The correct bar measurement helps you choose:

the right replacement chain
the right replacement guide bar
the correct drive link count
compatible pitch and gauge combinations

If you measure incorrectly, you may order the wrong chain loop or a bar that does not match your saw setup.

Called Length vs Overall Length

Called Length

Called length is the usable cutting portion of the guide bar.

This is the number usually used when buying a replacement bar or chain.

Overall Length

Overall length is the full metal length of the bar from one end to the other, including the section mounted inside the saw body.

This number is usually longer than the called length.

Simple Example

If the visible cutting portion measures about 15.8 inches, that is usually sold as a 16-inch guide bar.

The Easiest Way to Find Your Chainsaw Bar Length

Option 1: Check the Bar Tail

This is usually the fastest and easiest method.

Look near the mounting end of the guide bar for information such as:

bar length
pitch
gauge
part number
drive link requirement in some cases

Option 2: Use the Part Number on the Bar

Some bars include a part number that helps identify the called length.

On many Oregon bars, the first two digits of the stamped part number indicate the bar length in inches.

Option 3: Measure the Bar Manually

If the bar marking is unreadable, measure it yourself.

How to Measure a Chainsaw Bar Manually

Step 1: Turn off the saw

Make sure the chainsaw is fully powered off before measuring.

Step 2: Start at the front of the saw body

Place the tape measure at the point where the guide bar enters the saw body.

Do not start from the inner hidden mount section.

Step 3: Measure to the tip of the bar

Measure straight to the outermost tip of the guide bar.

Step 4: Round to the nearest whole inch

Round the result to the nearest standard size.

Example:

13.7" becomes 14"
15.8" becomes 16"
17.9" becomes 18"

What If You Want the Overall Bar Length?

If you want the total metal length of the guide bar, remove the bar and measure it from end to end.

Just remember that this is usually not the number used when buying a replacement bar or chain.

How Bar Length Affects Chain Size

Bar length is important, but it is not the only measurement needed for chain replacement.

To get the right chain, you still need:

pitch
gauge
drive link count

That is why two 16-inch bars do not always use the same chain.

Why Two 16-Inch Bars Can Use Different Chains

A 16-inch bar only tells you the approximate cutting length.

It does not automatically tell you:

pitch
gauge
drive link count
bar mount compatibility

For example, one 16-inch bar may use:

3/8" LP / .050" / 56DL

while another 16-inch bar may use:

.325" / .050" / 66DL

Both are 16-inch bars, but the chains are not interchangeable.

Common Standard Chainsaw Bar Lengths

For many homeowner saws, 14" to 18" is a common range, while larger gas saws often use longer bars depending on the saw class and cutting application.

How to Identify the Right Replacement Bar

Once you know your current bar length, confirm these additional details before buying a replacement:

bar length
pitch
gauge
bar mount pattern
drive link requirement for matching chain

Do not rely on bar length alone.

Common Mistakes When Measuring a Chainsaw Bar

Measuring the whole bar

This includes the hidden mounting section and gives you the wrong number.

Not rounding correctly

Called length should be rounded to the nearest whole inch.

Assuming all 16-inch bars are the same

They are not. Length alone does not determine the correct replacement chain or bar.

Ignoring the bar markings

The guide bar itself often contains the key size information you need.

Final Thoughts

If you want to measure a chainsaw bar correctly, measure the visible cutting length from the front of the saw body to the tip of the bar and round it to the nearest standard inch size.

That measurement is the called length, and it is the one most commonly used when buying a replacement bar or chain.

Once you know the bar length, make sure to also confirm the pitch, gauge, and drive link count before ordering a chain.

FAQ

Do you measure the whole chainsaw bar?

No. For replacement sizing, you usually measure the visible cutting length, not the full overall metal length.

How do I know if I have a 16-inch or 18-inch chainsaw bar?

Measure the visible cutting portion of the bar and round to the nearest inch.

Is bar length the same as chain length?

No. Chain fit also depends on pitch, gauge, and drive link count.

Where is the bar size marked?

It is often printed or stamped on the bar tail near the mounting end.

Can two 16-inch bars use different chains?

Yes. The correct chain also depends on pitch, gauge, and drive link count.

What if the markings are worn off?

Measure the bar manually, then confirm pitch, gauge, and drive links using the old chain, manual, or a fit guide.