How to Determine Chainsaw Bar Length? | Measure It Right

Measure from the front edge of the chainsaw housing to the bar tip, then round to the nearest even inch for the standard bar size.

Ordering the wrong replacement part usually starts with one simple error: measuring the whole bar instead of the part that actually cuts. A chainsaw bar’s size is its called length, or cutting length, which is the portion of the bar that extends beyond the saw body. That number, not the full metal length, is what you need to determine chainsaw bar length when you shop for a replacement.

How Do I Measure It?

Grab a tape measure, but protect yourself first. Then just three steps:

1. Secure the saw. Shut it off and engage the chain brake. Disconnect the power source on electric models; on gas saws, make sure the spark plug wire is not attached.
2. Measure the cutting portion. Run the tape from the front edge of the housing, where the bar emerges from the saw body, to the tip of the bar.
3. Round up. Round the result to the nearest even inch. A measurement of 15.5 inches becomes a 16-inch bar, and 17.5 inches becomes an 18-inch bar.

If you want to double-check, look for the length stamped on the bar’s tail. When no marking is visible, counting the drive links on the chain gives you a solid backup figure for matching a replacement.

What Length Fits the Job?

Start with what the saw was designed to carry. Manufacturer manuals or spec sheets list the maximum compatible bar length, chain pitch, gauge, and drive-link count, so that document beats any rule of thumb. From there, match the bar to the work you do most often. MU Extension offers a useful guide to common ranges. If you’re outfitting a long-bar saw, our tested 25-inch chainsaw bar options cover the professional end of that range.

Pairing the Bar With the Right Chain

Length is only one piece of the fit. The chain’s pitch, gauge, and drive-link count must also match the bar, the sprocket, and the bar groove. That is why ordering a bar by inches alone usually ends in a return trip. Husqvarna’s walkthrough explains why the called length is the measurement that matters for compatibility.

Wrong-length risks cut both ways. A bar that is too long can bog down the saw and increase wear; a bar that is too short simply reduces cutting capacity. A practical middle ground from MU Extension: use a bar slightly longer than the log or tree diameter, but not so long that the tip is likely to hit the ground or another branch while you work.

What About the Bar’s True Length?

True length means the full physical measurement from tip to the very end of the bar, including the tail section buried inside the saw. Family Handyman’s guide notes that this full length is not the size sold as a replacement. Because a portion of the bar sits inside the body, the true length always runs longer than the called length, so skip the end-to-end measurement when ordering.

The single most common mistake is measuring from the tip to the rear end of the bar instead of to the front edge of the saw housing. Do the measurement right, confirm the chain specs, and the replacement will slide on and cut without drama.