A replacement chainsaw chain must match three specifications: pitch, gauge, and drive-link count. Bar length helps narrow the search, but it does not uniquely identify a chain. Two 16-inch saws can use different gauges or different numbers of drive links, and a chain that is close—but not exact—can fit poorly or be unsafe to operate.
What the Chainsaw Chain Numbers Mean
| Specification | What it describes | Typical examples |
|---|---|---|
| Pitch | Spacing between chain rivets and compatibility with the drive sprocket | 3/8 in. LP, 3/8 in., .325 in. |
| Gauge | Thickness of the drive links that run inside the guide-bar groove | .043 in., .050 in., .058 in., .063 in. |
| Drive links (DL) | Number of links traveling in the bar groove; determines loop length | 45DL, 52DL, 55DL, 56DL, 62DL, 72DL |
1. Pitch: Matching the Chain to the Sprocket
Pitch describes the distance between chain components. It is calculated by measuring the distance across three consecutive rivets and dividing by two. In practice, the pitch is usually stamped on the guide bar, listed in the saw manual, or marked on the existing chain.
Low-profile 3/8-inch pitch is common on smaller homeowner saws. It is not automatically interchangeable with standard 3/8-inch chain. The cutter and safety geometry differ, and the chain must match the bar and sprocket system specified by the saw manufacturer.
2. Gauge: Matching the Guide-Bar Groove
Gauge is the thickness of the drive link. If the gauge is too thick, the chain will not enter or move freely in the bar groove. If it is too thin, the chain can wobble laterally, cut poorly, and increase wear. Common gauges include .043, .050, .058, and .063 inch.
Never estimate gauge by sight. The difference between .043 and .050 inch is small, but it is mechanically important.
3. Drive-Link Count: Matching the Loop Length
Drive-link count determines the chain loop's effective length. Count only the pointed links that travel inside the guide bar—not cutters or tie straps. The number is often printed on the original package, stamped on the bar, or included in the chain model description.
A chain with the correct pitch and gauge but the wrong drive-link count will be too short or too long for the bar and tensioning range.
Why Bar Length Alone Is Not Enough
Nominal bar length describes the approximate cutting length, not the exact chain loop. Bar mount pattern, nose design, sprocket configuration, and tensioner geometry can change the required drive-link count. For example, different 16-inch setups may require 55 or 56 drive links and may use .043 or .050 gauge.
Where to Find the Correct Specifications
- Guide-bar stamp: inspect both sides near the mounting end. Many bars list pitch, gauge, and drive links.
- Owner's manual: use the exact saw and bar configuration, not only the saw family name.
- Existing chain package: the three specifications are usually part of the label.
- Existing chain: count drive links and check manufacturer markings when the bar stamp is unreadable.
A Safe Replacement Checklist
- Disconnect the spark-plug lead or remove the battery before handling the chain.
- Confirm the bar currently fitted to the saw; it may not be the original bar.
- Match pitch exactly.
- Match gauge exactly.
- Match drive-link count exactly.
- Confirm cutter direction during installation.
- Set tension according to the saw manufacturer's procedure and recheck after the first cuts.
Worked Examples
Example A: 3/8 LP, .043, 45DL. All three values must appear on the replacement. A 3/8 LP, .050, 45DL chain has the right pitch and length but is too thick for a .043 bar groove.
Example B: 3/8 LP, .050, 56DL. A 55DL chain is not an acceptable substitute even if both are sold for a nominal 16-inch bar.
Example C: .325, .063, 68DL. This specification belongs to a different chain system than 3/8 LP. Matching only the 18-inch bar length would be insufficient.
Chainsaw Chains by Specification
12 Inch — 3/8 LP, .043, 45DLThree-pack for matching compact saw configurations.
16 Inch — 3/8 LP, .043, 55DLFor bars specifically marked with 55 drive links.
16 Inch — 3/8 LP, .050, 56DLA different gauge and drive-link count for another 16-inch setup.
18 Inch — 3/8 LP, .050, 62DLThree matching numbers for the correct replacement.
20 Inch — 3/8, .050, 72DLStandard 3/8-inch pitch single-loop chain.
18 Inch — .325, .063, 68DLAn example of a separate pitch and gauge system.
Frequently Asked Questions
What does DL mean on a chainsaw chain?
DL means drive links. It is the count of the links that run inside the guide-bar groove.
Can I use .050 chain on a .043 bar?
No. The drive links are too thick for the groove. Pitch, gauge, and drive-link count must all match.
Does the saw model guarantee the chain size?
Not always. A saw may accept multiple bar configurations, and a replacement bar may differ from the original. Verify the specifications on the bar currently installed.
Match Your Replacement Chain Correctly
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