Chainsaw Chain Code Identification: Read the Numbers Stamped on Your Chain (Aussie Guide)
Every chainsaw chain has a short code stamped right on it, and that code tells you the two things you need to order the right replacement: the pitch and the gauge. Get those two right and the chain fits your bar and sprocket; get them wrong and it won't run. This guide shows you exactly where to look, what the numbers mean, and how to cross-reference Oregon, Carlton, Stihl and Husqvarna codes so you can match your chain with confidence.
Where to find the code on your chain
The code is stamped onto the drive links — the small teeth on the underside of the chain that sit down inside the bar groove and get driven by the sprocket. It isn't on every link, so you'll need to rotate the chain by hand and watch the bottom edge until a stamped link comes around. On a fitted chain, pull it gently around the bar (engine off, chain brake off) and keep an eye on the drive links as they pass the bar tip or sprocket. Off the saw, just walk it through your hands.
Different brands stamp it differently:
-
Oregon and Carlton stamp a short identification code on the drive link — usually one or two digits, sometimes a letter and a number (like
72orK2). That code is the quick lookup. -
Stihl doesn't stamp a short drive-link code the same way — Stihl chains are sold and identified by a part number (like
33RMor63PM3), which you'll find on the box, the packaging label, or stamped on the chain depending on the run. -
Husqvarna uses a two-digit code stamped on the drive link (like
21or45).
If you can read the code, the tables below tell you the pitch and gauge straight away. If it's worn off, skip down to the "code worn off or not listed" section.
What pitch and gauge actually mean
Two measurements decide whether a chain fits. Get your head around these and the codes make sense.
Pitch is the distance between the rivets, measured a particular way and then expressed as a fraction of an inch. The common ones are 1/4", .325", 3/8" low-profile (LP), 3/8" and .404". Pitch has to match your bar and your sprocket — the drive sprocket is cut for a specific pitch, so a 3/8" chain won't seat properly on a .325" sprocket.
Gauge is the thickness of the drive link — the part that rides in the bar groove. It has to match your bar's groove width, otherwise the chain is either too loose and rattles or too thick to drop in. Gauge is stamped in inches, but we always give you the metric pair too because that's what you'll often see on AU bars and packaging:
- .043 = 1.1mm
- .050 = 1.3mm
- .058 = 1.5mm
- .063 = 1.6mm
- .080 = 2.0mm
The golden rule: bar, chain and sprocket must all share the same pitch, and the chain gauge must match the bar groove. Match those and you're sorted.
Stihl → Oregon conversion
If you know your Stihl part number you can find the equivalent Oregon chain, and vice versa. Pitch and gauge are listed in inches with the mm pair.
| Stihl part no. | Oregon code | Pitch | Gauge in (mm) |
|---|---|---|---|
| 13RM, 13RMS | 25AP | 1/4" | .050 (1.3mm) |
| 61PMM3 | 90PX | 3/8" LP | .043 (1.1mm) |
| 63PM3 | 91P | 3/8" LP | .050 (1.3mm) |
| 63PM1, 63PMC3 | 91VXL | 3/8" LP | .050 (1.3mm) |
| 23RM, 23RMC | 95TXL | .325" | .050 (1.3mm) |
| 23RMC, 23RM2 | 20BPX | .325" | .050 (1.3mm) |
| 23RS, 23RSC, 23RSC3 | 20LPX | .325" | .050 (1.3mm) |
| 25RM, 25RMC, 25RM2, 25RMC3 | 21BPX | .325" | .058 (1.5mm) |
| 25RSC3 | 21LPX | .325" | .058 (1.5mm) |
| 26RM, 26RMC, 26RMC3 | 22BPX | .325" | .063 (1.6mm) |
| 26RS, 26RSC, 26RSC3 | 22LGX | .325" | .063 (1.6mm) |
| 33RM, 33RMC, 33RMC3 | 72DPX | 3/8" | .050 (1.3mm) |
| 33RMF | 72APX | 3/8" | .050 (1.3mm) |
| 33RS, 33RSC | 72EXL | 3/8" | .050 (1.3mm) |
| 33RSC3 | 72LPX | 3/8" | .050 (1.3mm) |
| 33RSF | 72EXJ | 3/8" | .050 (1.3mm) |
| 33RSLK | 72CL | 3/8" | .050 (1.3mm) |
| 33RSLHK | 72CK | 3/8" | .050 (1.3mm) |
| 33RSLF | 72CJ | 3/8" | .050 (1.3mm) |
| 35RM, 35RMC, 35RMC3 | 73DPX | 3/8" | .058 (1.5mm) |
| 35RS, 35RSC | 73EXL | 3/8" | .058 (1.5mm) |
| 35RSC3 | 73LPX | 3/8" | .058 (1.5mm) |
| 35RSF | 73EXJ | 3/8" | .058 (1.5mm) |
| 36RM, 36RMC, 36RMC3 | 75DPX | 3/8" | .063 (1.6mm) |
| 36RS, 36RSC | 75EXL | 3/8" | .063 (1.6mm) |
| 36RSC3 | 75LPX | 3/8" | .063 (1.6mm) |
| 36RSF | 75EXJ | 3/8" | .063 (1.6mm) |
| 36RSLK | 75CL | 3/8" | .063 (1.6mm) |
| 36RSLHK | 75CK | 3/8" | .063 (1.6mm) |
| 36RSLFK | 75CJ | 3/8" | .063 (1.6mm) |
A handy pattern to remember: in the 3/8" Stihl range, 33 = .050 (1.3mm), 35 = .058 (1.5mm) and 36 = .063 (1.6mm). The first two digits of the Stihl number step up with the gauge.
Carlton drive-link codes
Carlton stamps a letter-and-number code on the drive link. Find it, then read across.
| Code | Pitch | Gauge in (mm) |
|---|---|---|
| E1 | 1/4" mini | .050 (1.3mm) |
| K1 | .325" | .050 (1.3mm) |
| K2 | .325" | .058 (1.5mm) |
| K3 | .325" | .063 (1.6mm) |
| N4, N | 3/8" LP | .043 (1.1mm) |
| N1 | 3/8" LP | .050 (1.3mm) |
| A1 | 3/8" | .050 (1.3mm) |
| A2 | 3/8" | .058 (1.5mm) |
| A3 | 3/8" | .063 (1.6mm) |
| B1 | .404" | .050 (1.3mm) |
| B2 | .404" | .058 (1.5mm) |
| B3 | .404" | .063 (1.6mm) |
The Carlton logic is easy once you spot it: the letter is the pitch family (K = .325", A = 3/8", B = .404") and the number is the gauge step (1 = .050/1.3mm, 2 = .058/1.5mm, 3 = .063/1.6mm).
Oregon drive-link codes
Oregon's code is the first one or two digits of the chain name (the 72 in 72DPX, for example). Here's the full pitch-and-gauge lookup.
| Code | Pitch | Gauge in (mm) |
|---|---|---|
| 25 | 1/4" mini | .050 (1.3mm) |
| 20 | .325" | .050 (1.3mm) |
| 21 | .325" | .058 (1.5mm) |
| 22 | .325" | .063 (1.6mm) |
| 19 | .325" | .063 (1.6mm) |
| 33 | .325" | .050 (1.3mm) |
| 34 | .325" | .058 (1.5mm) |
| 35 | .325" | .063 (1.6mm) |
| 95 | .325" | .050 (1.3mm) |
| 90 | 3/8" LP | .043 (1.1mm) |
| 91 | 3/8" LP | .050 (1.3mm) |
| 72 | 3/8" | .050 (1.3mm) |
| 76 | 3/8" | .050 (1.3mm) |
| 73 | 3/8" | .058 (1.5mm) |
| 77 | 3/8" | .058 (1.5mm) |
| 75 | 3/8" | .063 (1.6mm) |
| 78 | 3/8" | .063 (1.6mm) |
| 28 | .404" | .050 (1.3mm) |
| 50 | .404" | .050 (1.3mm) |
| 26 | .404" | .058 (1.5mm) |
| 51 | .404" | .058 (1.5mm) |
| 58 | .404" | .058 (1.5mm) |
| 27 | .404" | .063 (1.6mm) |
| 52 | .404" | .063 (1.6mm) |
| 59 | .404" | .063 (1.6mm) |
| 68 | .404" | .063 (1.6mm) |
| 16 | .404" | .063 (1.6mm) |
| 18 | .404" | .080 (2.0mm) |
| 9 | 1/2" | .058 (1.5mm) |
| 10 | 1/2" | .063 (1.6mm) |
| 11 | 3/4" | .122 (3.1mm) |
Note that a couple of common .325" codes (19, 35) are the higher .063 (1.6mm) gauge — worth double-checking your bar groove before ordering, since .325" chain is sold in three gauges.
Husqvarna chain codes
Husqvarna stamps a two-digit code on the drive link. Read it off, then look it up here.
| Code | Pitch | Gauge in (mm) |
|---|---|---|
| 00 | 1/4" | .050 (1.3mm) |
| 22, 23, 30, 37, 78 | .325" | .050 (1.3mm) |
| 21, 25, 38 | .325" | .058 (1.5mm) |
| 26 | .325" | .063 (1.6mm) |
| 35, 36 | 3/8" LP | .050 (1.3mm) |
| 46, 47, 51, 80, 82 | 3/8" | .050 (1.3mm) |
| 42, 48, 54, 81 | 3/8" | .058 (1.5mm) |
| 45, 50, 83 | 3/8" | .063 (1.6mm) |
| 69 | .404" | .058 (1.5mm) |
| 57, 64, 65 | .404" | .063 (1.6mm) |
Use our Chain Finder to match your chain
If you'd rather not hunt through tables, our Chain Finder does the cross-referencing for you. Punch in what you know — your saw model, the code on the chain, or the bar markings — and it points you to the matching chain in our range.
You can also open it on its own page here: farmandacreco.com.au/pages/chain-finder. For working out drive-link counts and bar length, the Chainsaw Chain Calculator is the companion tool.
My code is worn off or not listed
It happens — codes get worn smooth on a well-used chain, or you've got an older or less common brand that isn't in the tables. Here's how to nail it down anyway:
- Send us a photo. Snap a clear shot of the chain (and the bar tip and the bar markings if you've got them) and send it through. We can usually work out the pitch and gauge pretty quickly from a photo.
- Count the drive links. Lay the chain out or rotate it around the bar and count every drive link. That number, plus the pitch, tells us the exact loop you need.
- Measure the gauge. If you've got vernier calipers, measure the drive-link thickness — that gives you the gauge directly (e.g. 1.3mm = .050).
- Read your bar. Most bars are stamped with pitch and gauge near the mount end. If the chain code is gone, the bar often still has the numbers.
- Use the Chain Finder above, or give us a ring on 0431 183 421 and we'll talk it through.
For more on sizing, bar lengths and drive-link counts, have a look through our chainsaw guide blog.
FAQ
Where is the code on a chainsaw chain?
It's stamped on the drive links — the teeth on the underside of the chain that sit in the bar groove. It's not on every link, so rotate the chain by hand (engine off, chain brake off) and watch the bottom edge until a stamped link comes around. Oregon and Carlton stamp a short code there; Husqvarna stamps a two-digit code; Stihl is identified by a part number on the box or packaging.
What does .325 vs 3/8 mean on a chain?
Both are pitch measurements — the spacing between the rivets, given as a fraction of an inch. .325" is a slightly tighter spacing common on mid-size saws, while 3/8" is the most common pitch on bigger farm and pro saws. They're not interchangeable: your bar and drive sprocket are cut for one pitch, so the chain has to match it.
My chain says 21BPX — what is it?
The Oregon code is the leading number, 21, which is .325" pitch in .058 (1.5mm) gauge. The Stihl equivalent is the 25RM family (25RM, 25RMC, 25RM2, 25RMC3). So a 21BPX is a .325" pitch, .058 (1.5mm) gauge chain — just confirm your drive-link count to get the exact loop length.
Is .058 the same as 1.5mm?
Yes. .058" and 1.5mm are the same gauge, just inches versus metric. The full set we use is .043 (1.1mm), .050 (1.3mm), .058 (1.5mm), .063 (1.6mm) and .080 (2.0mm). Match the gauge to your bar groove width.
Can I put a 3/8 chain on a .325 bar?
No. The pitch has to match across the bar, chain and sprocket. A 3/8" chain won't seat correctly on a .325" sprocket or bar, even if the gauge happens to line up. If you want to change pitch you'd need to change the sprocket and bar to suit as well.
Quick reference
- The chain code is stamped on the drive links (underside, in the bar groove). Rotate the chain to find a stamped link.
- Oregon/Carlton = short stamped code · Husqvarna = two-digit code · Stihl = part number on the box.
- The code gives you pitch (rivet spacing: 1/4", .325", 3/8" LP, 3/8", .404") and gauge (drive-link thickness).
- Gauge in inch + mm: .043 (1.1mm), .050 (1.3mm), .058 (1.5mm), .063 (1.6mm), .080 (2.0mm).
- Bar, chain and sprocket must all share the same pitch; chain gauge must match the bar groove.
- Stuck? Photo it, count the drive links, use the Chain Finder, or ring 0431 183 421.
Need a hand matching your chain?
Send us a photo of your bar or chain and we'll work out the pitch, gauge and drive-link count for you — quickest way to get the right loop first time. Or run it through the Chain Finder above, or call 0431 183 421. Ready to order? Browse our tungsten carbide tipped chainsaw chains and bars — they stay sharp and last up to 10x longer than standard steel in hardwood.