How to determine your Chain Size

Determine the Size of Your Chain

When your chainsaw chain gets old or dull, it’s time for a new one. But chains come in different sizes, just like shoes, so you need the right size or it won’t fit or work properly.

To choose the right chain, you only need three numbers. Think of them as the chain’s secret code.

🔢 The Three Numbers You Need

1. Pitch - how far apart the little round rivets on the chain are.

Common pitch sizes:

• .325" (8.25mm) — used on mid‑range saws around 40cc

• 3/8" (0.375" / 9.52mm) — used on big saws over 50cc, and also many small petrol and battery saws up to 35cc

How to find your pitch:

• Count 3 rivets in a row

• Measure from the middle of the first to the middle of the third

• Divide that number by 2

That number is your pitch.
(You can also check your bar near the mount, or manual — it’s usually printed there.)

2. Gauge

Gauge is how thick the bottom part of the chain is — the part that slides inside the bar.

• Gauge is measured in fractions of an inch or in millimetres

• It’s hard to measure with a normal ruler, so most people read it from the bar or manual

• Common gauges are .043 / 1.1mm, .050 / 1.3mm, .058 / 1.5mm, .063 / 1.6mm

If the gauge is wrong:

• Too thick → won’t fit in the bar

• Too thin → chain will be loose, unsafe, and wear out early

3. Drive Link Count (DL)

Drive links are the little “shark fins” on the bottom of the chain.
Cutters are the “teeth” on top that chew the wood.

A quick way to count drive links:

• Take the chain off the saw

• Hold it in your left hand

• Line up a pair of cutters at the top

• Count the cutters in pairs

• Double that number — that’s usually your drive link count

Chains with an odd number of drive links:
Some chains have an extra joiner link. You’ll see a slightly bigger gap between two cutters. 

Example:

• You count 27 cutters

• 27 × 2 = 54

• But you spotted the extra joiner → so the chain is 55DL

This number must be exact or the chain won’t fit your bar.

🎉 Once You Have These Three Numbers

With pitch, gauge, and drive link count, you know the exact chain size your saw needs. You can now choose the perfect replacement every time.

Next Step: Buy the Chain

Let’s use an example.
You have a Stihl MS180 with a 16‑inch bar.
Its chain size is: 3/8 (pitch), .043 (gauge), 55DL.

To find it:

• Go to www.toughmax.com.au

• Click the search magnifying glass

• Type: 3/8 .043 55DL

• Choose any product with those three numbers in the title