Chainsaw Bar Stamping Numbers (Pitch & Gauge Specs)
To choose a replacement chain, read the bar’s markings, then confirm pitch, gauge, and drive-link count. Match pitch to the saw’s drive sprocket and gauge to the bar groove. Check the saw manual for approved bar fitment; bar length alone cannot prove compatibility. Marking formats vary, so use the bar model number and manufacturer chart if a stamp is unclear.
Could you identify the right chain in the shed without guessing or buying twice? The key is to treat the bar stamp as a set of clues, not a complete fitment guarantee. Below, I’ll show you what each number means, what else to check, and how to handle a stamp that is worn or hard to read.
How to read the numbers stamped on a chainsaw bar
A bar stamp may list nominal bar length, chain pitch, groove gauge, and sometimes a model code or drive-link count. The order and abbreviations are not standard across brands. Read the full marking, then check the bar model or saw manual before choosing a chain.
Look along the bar body, often near the mounting end, for a stamped or printed group of letters and numbers. A marking might include a length such as 16 in., a pitch such as .325 in., and a gauge such as .050 in. Some bars include only part of this information.
Do not assume that the first number is pitch or that the last number is drive-link count. Manufacturers use different layouts, and a short code may identify a bar series rather than a chain size. If the marking is faded, record the bar brand and model number, then check that manufacturer’s parts chart.
“Bar length” usually refers to the nominal cutting length, but the exact way it is stated can vary. Use the length listed for the saw and bar model, not a tape measure alone, to identify fitment. The length does not reveal the chain’s pitch, gauge, or required link count.
What pitch, gauge, and drive links mean
Pitch, gauge, and drive-link count are three separate chain dimensions. Pitch must match the bar’s sprocket system and the saw’s drive sprocket. Gauge must match the bar groove. Drive-link count must match the exact bar setup; all three dimensions matter when selecting a replacement chain.
Pitch describes the spacing of the chain’s rivets. Measure from the center of one rivet to the center of the third rivet, then divide that distance by two. Common markings include .325 in. and 3/8 in. low-profile, often written as 3/8P.
Gauge is the thickness of each chain drive link, the part that runs inside the bar groove. Common sizes include .043, .050, .058, and .063 in. The chain maker’s specification is the safest reference. A drive link that is too thick may not fit the groove; one that is too thin may sit loosely.
Drive-link count is the number of drive links around the chain. It determines chain length for that bar-and-saw setup. Two bars with the same nominal length can require different link counts because mounting, bar design, or chain configuration can differ. Use the chain maker’s chart for the exact bar model.
| Marking or spec | What it tells you | What it must match |
|---|---|---|
| .325 in. or 3/8P | Chain pitch | Bar system and saw drive sprocket |
| .043, .050, .058, or .063 in. | Drive-link thickness | Bar groove gauge |
| Drive-link count, such as a listed number in a chain chart | Chain length | Exact bar model and saw setup |
| 16 in. or another nominal length | Bar size class | Saw maker’s approved bar range |
These are examples of common markings, not a universal combination chart. A particular pitch can be offered in more than one gauge, and a particular bar length can have more than one possible chain configuration. Confirm the full specification before ordering.
How to confirm the chain fits your saw
A bar stamp helps identify a chain, but the saw’s approved fitment is the final check. The bar, chain, and drive sprocket must work as a matched system. Check the saw manual or manufacturer parts information for the sprocket pitch, approved bar models, and chain specification.
Use this order when checking compatibility:
- Find the saw model number and consult its manual or official parts chart.
- Confirm the drive sprocket pitch. It must match the chain pitch.
- Confirm the bar’s groove gauge and match it to the chain gauge.
- Find the required drive-link count for the exact bar model.
- Confirm that the bar model and length are approved for the saw.
Do not choose a bar only because its length seems suitable for the engine size. There is no universal bar-length-to-displacement ratio that establishes fitment. Bar length is one part of the manufacturer’s approved setup, not a substitute for checking pitch, gauge, and chain length.
Also distinguish 3/8 in. low-profile from standard 3/8 in. pitch. The markings and systems are not automatically interchangeable. Match the exact pitch specified for the bar and sprocket, rather than relying on the phrase “three-eighths” alone.
Two common stamp-reading problems
A stamp can be incomplete, worn, or easy to misread. In those cases, use the bar’s model number and the saw’s parts information to verify the full chain specification. These examples show how to narrow down a mismatch without treating bar length as proof.
Example 1: The stamp shows 16 in. and .050, but no pitch. The gauge is useful, but it does not identify pitch or link count. I would check the bar model number, then compare it with the saw manual or the bar maker’s chart. I would not buy a chain based only on “16 in., .050.”
Example 2: The chain fits the groove but does not match the sprocket. A gauge match alone is not enough. If the chain pitch differs from the drive sprocket pitch, the setup is incompatible. Stop and confirm the saw’s sprocket specification and the bar’s required chain pitch before running it.
Example 3: The pitch and gauge match, but the chain is too long or short. Check the drive-link count for the exact bar model. Do not try to solve the problem by forcing the adjuster to its limit. The wrong link count can prevent correct tensioning.
These are diagnostic examples, not a substitute for the manufacturer’s parts data. If the bar has no readable code and the model cannot be identified, have a dealer or qualified service shop verify the parts before use.
Checks before fitting or running the chain
The right numbers do not make a damaged or poorly fitted chain safe. With the saw off and the engine disabled, check the bar, chain, sprocket, and safety parts. Follow the saw manual for installation and tensioning, and do not run a loose, damaged, or dry chain.
Before fitting, wear suitable protective equipment and keep bystanders clear. Inspect the chain brake, controls, chain catcher, bar, and chain for damage. Clean debris from the bar groove and oil passages. Look for burrs, damaged rails, or uneven wear; flip the bar only if its maker permits it.
After fitting the specified bar and chain, check orientation, lubrication, and tension according to the manual. With the engine disabled and gloves on, verify that the chain moves freely by hand. Do not start the saw if the chain binds, is loose, or fails to receive oil.
A wrong-gauge chain, incorrect link count, or loose chain can leave the bar groove or sprocket. Stop immediately if the chain jumps, loses tension, or lubrication fails. Find and correct the cause before restarting. Bar stampings identify parts; they do not tell you how to direct a cut or whether a tree is safe to fell.
Frequently asked questions
These short answers cover the most common questions about bar markings and replacement-chain fit. If a stamp conflicts with the saw manual or manufacturer parts chart, pause and verify the exact bar and sprocket setup rather than guessing from length.
What do the numbers on a chainsaw bar mean?
They may identify nominal bar length, chain pitch, groove gauge, and sometimes a model code or drive-link count. The order and abbreviations vary by manufacturer.
Does bar length tell me which chain to buy?
No. Length alone does not establish pitch, gauge, or drive-link count. Use the exact bar model and manufacturer chain chart.
What is chainsaw chain pitch?
Pitch is the distance from the center of one rivet to the center of the third rivet, divided by two. It must match the bar system and drive sprocket.
What does .050 mean on a bar?
It usually identifies a .050-inch groove gauge. The replacement chain’s drive-link thickness must match the bar groove.
Can I use a .050 chain in a .058 bar?
Do not assume they are interchangeable. Match the chain gauge to the bar maker’s specification; a mismatch can cause poor fit or unsafe chain movement.
How do I find the drive-link count?
Check the chain maker’s chart for the exact bar model and length, or use the saw maker’s parts information. Bar length alone does not give a reliable count.
Is 3/8P the same as 3/8-inch pitch?
No. 3/8P refers to 3/8-inch low-profile pitch. Confirm the exact system specified for the bar and sprocket.
Can I use any bar with the same pitch and gauge?
No. The saw must approve the bar model and length, and the chain must also have the correct drive-link count. Verify fitment in the manual or official parts chart.
What if the bar stamp is unreadable?
Find the bar model number and check the manufacturer’s parts chart. If neither can be identified, ask a qualified dealer or service shop to verify the setup before use.
Does a longer bar require a different pitch?
Not by itself. Pitch is set by the compatible bar-and-sprocket system. The manufacturer’s approved bar range and the exact chain specification still apply.
(This article was written by one of our staff writers, David Hensley. Visit our Meet the Team page.)
