To measure a chainsaw chain you need three numbers: the pitch, the gauge, and the drive-link count. Pitch is the distance between any three rivets divided by two. Gauge is the thickness of the drive links that ride in the bar groove. Drive-link count is the total number of drive links in the loop. Together these three specs identify your chain exactly — bar length alone does not.
Walking into a shop and asking for a "standard 18-inch chain" is like asking a tyre shop for a "standard round tyre." It doesn't exist. Chainsaw cutting systems are precision loops with tolerances measured in thousandths of an inch, and getting a measurement wrong ranges from a chain that won't mount to catastrophic damage to your clutch drum and bar rails. Here's how to get all three numbers right.
The "Bar Length" Trap
Before you touch a set of calipers, dispel the most common myth in the industry: bar length is not a chain specification. The "18-inch" printed on your bar refers to the cutting length (how much bar sticks out of the saw), not the length of the chain loop.
One brand's 18-inch saw might run 68 drive links. Another brand's 18-inch saw runs 72.
Never buy a chain on bar length alone — you must know the pitch, gauge and drive-link count.
What Is Chainsaw Chain Pitch?
Chain pitch is the distance between any three consecutive rivets on the chain, divided by two. It effectively sets the "size" of the chain and must match your drive sprocket (on the engine) and nose sprocket (on the bar tip) — all three have to mesh perfectly.
How to Measure Pitch
Lay the chain flat on a bench.
With calipers or a ruler, measure from the centre of the first rivet to the centre of the third rivet.
Divide that number by 2. That is your pitch.
The Common Pitches
1/4": Carving bars and pole pruners.
3/8" LP (Low Profile / Picco): Small Stihl (MS 170/180), battery saws and domestic saws.
.325": The most common mid-range size, for 40cc–60cc farm saws.
3/8" Standard: The professional standard for 70cc+ felling saws.
.404": Heavy-duty harvesters and old-school muscle saws.
Warning: 3/8" LP and 3/8" Standard calculate to the same pitch (0.375") but are not interchangeable — LP uses a lower chassis height. Running a Standard chain on an LP sprocket will destroy the drive-link tangs. (See our 3/8" LP vs 3/8" Standard guide.)
What Is Chainsaw Chain Gauge?
Gauge is the thickness of the drive link — the shark-fin-shaped tang that rides inside the groove of your guide bar. It is the fitment tolerance that keeps the chain standing up straight while it cuts, and it must match your bar groove exactly.
How to Measure Gauge
Clean the oil and sawdust off a drive link.
Clamp a set of vernier calipers over the thickest part of the drive link (away from the worn bottom edge).
Read the measurement in thousandths of an inch.
The Four Gauges
.043" (1.1mm): Narrow-kerf. Pole pruners, battery/electric saws, and the Stihl MS 170/180 series.
.050" (1.3mm): The global standard — used on around 80% of chainsaws worldwide.
.058" (1.5mm): Common on Husqvarna, Echo and Jonsered. Visually near-identical to .050", which causes constant confusion.
.063" (1.6mm): Heavy-duty, used mainly by Stihl on professional and Farm Boss saws — and, in Australia, on many Stihl saws where other markets use .050".
Pitch vs Gauge — What's the Difference?
They're easy to mix up but measure different things. Pitch is how far apart the links are (the chain's size class); gauge is how thick the drive links are (how it fits the bar groove). A chain is only correct when both match your saw — the right pitch on the wrong gauge still won't fit.
What Happens If the Gauge Is Wrong
Too thin (e.g. .050" chain in a .058" bar): the chain leans side to side, cuts in a curve, and wears the bar rails fast.
Too thick (e.g. .058" chain in a .050" bar): it won't seat in the groove, and forcing it seizes the nose sprocket and burns the bar tip.
What Are Drive Links, and How Do You Count Them?
The drive-link count is the total number of drive links in the loop — the only accurate way to state chain length. "18 inches" is a marketing term; "68 drive links" is an engineering specification.
What Does "DL" Mean on a Chainsaw Chain?
"DL" is short for drive links — the number of drive links in the chain loop. When a chain or bar is marked "72 DL" it means the loop has 72 drive links (the tangs that ride inside the bar groove). It's the same thing as the drive-link count, and it's how chain length is stated accurately, because bar length alone doesn't pin it down. You'll sometimes see it written as "DL", "D/L" or just "Links" on the tail of a guide bar.
How to Count Drive Links
Take the chain off the saw.
Mark one drive link with a paint pen or a piece of tape — this is your "zero."
Count the drive links (the tangs that ride inside the bar groove), not the cutters on top.
Continue right around the loop until you reach your mark.
Why the Count Varies Between Saws
Different manufacturers place the bar mounting studs at different distances from the drive sprocket, so the same nominal bar length needs a different number of links:
A Stihl 18" bar typically takes 66–68 drive links.
A Husqvarna 18" bar typically takes 72 drive links.
An Echo 18" bar might take 70.
Order a "72-link" chain for an 18" Stihl and it'll be four links too long — your tensioner maxes out before the chain is tight.
The Shortcut: Read the Stamps Instead of Measuring
You often don't need calipers at all. Both your chain and your bar usually carry the numbers already:
On the chain: most brands stamp an identification code on the drive link that decodes to pitch and gauge. Our chainsaw chain identification chart translates the Stihl, Oregon, Carlton and Husqvarna codes, and our chainsaw chain cross reference chart maps those codes to the matching Alpine size.
On the bar: the tail of the guide bar (near the mounting slot) is usually stamped with the pitch, gauge and drive-link count directly.
The Accuracy Hierarchy
Best: read the code stamped on your old chain's drive link.
Better: measure with calipers using the methods above.
Good: read the stamp on the tail of your guide bar.
Risky: guessing from bar length.
Found Your Numbers? Find Your Chain
Once you have your pitch, gauge and drive-link count, drop them into our Search by Bar Stamp tool and we'll show you the exact chain — or if you'd rather look it up by machine, use Search by Chainsaw and enter your model. Prefer to browse? Our complete saw chain size guide lists every model we fit.
How to Measure a Chainsaw Chain — FAQ
How do you measure a chainsaw chain?
Measure three things: pitch (distance between three rivets, divided by two), gauge (drive-link thickness, with calipers), and drive-link count (count every drive link around the loop). All three must match your saw and bar.
What does DL mean on a chainsaw chain?
DL means drive links — the number of drive links in the chain loop. A chain marked "72 DL" has 72 drive links. It's the accurate way to state chain length, since bar length alone can correspond to different link counts.
What is the pitch of a chainsaw chain?
Pitch is the distance between any three consecutive rivets divided by two. Common pitches are 1/4", 3/8" low profile, .325", 3/8" standard and .404". It sets the chain's size class and must match your sprockets.
What is chainsaw chain gauge?
Gauge is the thickness of the drive links that ride in the bar groove — .043", .050", .058" or .063". It must match your bar exactly; too thick won't fit, too thin lets the chain lean and cut crooked.
How do I count the drive links on a chainsaw chain?
Take the chain off the saw, mark one drive link as a starting point, and count the drive links (the tangs inside the bar groove, not the top cutters) all the way around until you return to your mark.
Can I measure a chainsaw chain by its bar length?
No. Bar length is a rough guide only — the same bar length can take different drive-link counts depending on the saw. Always confirm pitch, gauge and drive-link count from the chain or bar stamp.
Need the right chain for your saw?
Don't guess — match it exactly. Read the pitch, gauge and drive-link count off your bar and we'll find your precise chain, or search by your saw model. Every chain is backed by our Guaranteed Fit promise, checked against your bar stamp before it ships.