You shouldn't have to guess what chainsaw chain you are running. The answer is usually written right on the metal.
Most reputable chainsaw chain manufacturers—including Stihl, Oregon, Carlton, and Husqvarna—stamp a specific identification code directly onto the Drive Link (the bottom tooth that rides in the bar groove).
These codes are the "DNA" of your chain. If you know how to read them, they tell you the exact Pitch and Gauge without you ever needing to pick up a set of calipers.
At Alpine Chain Co, we know these codes can look like hieroglyphics. This guide breaks down the secret languages of the major brands so you can confidently order the correct Alpine Chain Co. model.
Where to Look
Before you start reading, you need to clean your chain.
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Find the Drive Link: This is the shark-fin-shaped link that sits inside the bar groove.
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Scrub it: Use a wire brush or some petrol on a rag to wipe away the oil and sawdust.
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Find the Number: Look for a small stamped number or letter combination (e.g., "91", "21", "3", "73").
The Master Identification Chart
Different brands use different coding systems. Find your brand below to decode your chain.
1. Stihl Chains (The "Two-Part" System)
Stihl is unique. They often split their identification between the Cutter (Pitch) and the Drive Link (Gauge).
Step A: Check the Drive Link (Finds the Gauge)
Stihl stamps the last digit of the gauge measurement on the drive link.
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1 = .043" (1.1mm)
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3 = .050" (1.3mm) – Most Common
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5 = .058" (1.5mm)
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6 = .063" (1.6mm) – Standard for Stihl Farm/Pro Saws
Step B: Check the Cutter (Finds the Pitch)
Look at the side of the cutting tooth itself.
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6 (or P) = 3/8" LP (Picco)
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2 = .325"
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3 = 3/8" Standard
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4 = .404"
Example: You see a "3" on the drive link and a "2" on the cutter.
3 = .050" Gauge.
2 = .325" Pitch.
Result: You need a .325" .050" Chain.
2. Oregon Chains (The "Series" System)
Oregon uses a two-digit code stamped on the drive link. This code defines the "Series," which tells you both Pitch and Gauge.
| Stamp Code | Pitch | Gauge | Common Application |
| 90 | 3/8" LP | .043" | Small Stihl/Battery Saws |
| 91 | 3/8" LP | .050" | Homeowner/Arborist Saws |
| 20 | .325" | .050" | Husqvarna/Echo Farm Saws |
| 21 | .325" | .058" | Husqvarna Standard |
| 22 | .325" | .063" | Stihl Replacement |
| 95 | .325" | .050" | Narrow Kerf Systems |
| 72 | 3/8" Std | .050" | Pro Felling Saws |
| 73 | 3/8" Std | .058" | Pro Husqvarna Saws |
| 75 | 3/8" Std | .063" | Pro Stihl Saws |
Example: You see "73" stamped on the link.
Result: You need a 3/8" Standard / .058" Gauge Chain.
3. Husqvarna Chains (The "H" System)
Husqvarna chains are often manufactured by Oregon (historically) or in their own Swedish factory (X-Cut). They typically use "H" or "S" codes, though the drive link often still bears the Oregon-style number.
| Husky Code | Drive Link Stamp | Pitch | Gauge |
| H37 | 91 | 3/8" LP | .050" |
| H23 | 20 | .325" | .050" |
| H25 | 21 | .325" | .058" |
| C85 / S85 | 73 or C85 | 3/8" Std | .058" |
| H42 | 73 | 3/8" Std | .058" |
The Next Step: Confirming the Length
Finding the code solves the Pitch and Gauge mystery. But the stamp does not tell you the length.
Even if you find a "73" stamp (3/8 .058), you still need to know how many links are in your loop.
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Option 1: Count the drive links manually.
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Option 2: Look for the stamp on the tail of your guide bar (near the oiler hole). It will often say "DL" or "Links" followed by a number like 68, 72, or 84.
Ready to Upgrade?
Now that you have decoded your old chain, replace it with Alpine Chain Co. Engineered to stay sharp longer in Australian hardwood.