Chainsaw Bar Length Guide — What Size Bar Do You Need? (2026)

Bar length sets how thick a cut you can make in one pass, but you can only fit the lengths your saw’s maker lists. Here is how to choose a length for your work from the options approved for your saw.

Bar Length by Task and Engine Size

Makers list the bar lengths each saw is approved for. Some examples from their manuals and product pages:

The key principle: use a bar length the maker lists for your saw. Makers publish approved bar and chain combinations — Husqvarna, for example, says its 445 II and 450 II meet the EN ISO 11681-1 chainsaw safety requirements when fitted with the guide bar and chain combinations listed in the manual.

Why Bar Length Matters

Your bar length determines:

• Cutting length: a bar’s called length is its cutting length, which Oregon measures from the front of the saw to the tip of the guide bar, rounded to the nearest inch.
• Kickback zone: Husqvarna says kickback happens when the kickback zone at the nose of the guide bar touches an object.
• Approval: Husqvarna, for example, says its 445 II and 450 II meet the EN ISO 11681-1 chainsaw safety requirements when fitted with the guide bar and chain combinations listed in the manual.

Battery Chainsaw Bar Lengths

Battery saws come in a range of bar lengths: from 20 cm (Milwaukee M18 FHS20) to 50 cm (DEWALT DCMCS575 and Milwaukee M18 F2CHS50) in the maker data we checked. We have no maker data comparing battery-motor and petrol-engine torque.

Bar lengths makers list for some battery saws:

• Single 18V battery: Makita DUC254 25 cm, DEWALT DCM565 30 cm, Milwaukee M18 FCHS 40 cm
• Two 18V batteries: Makita DUC353 and DUC405 300–400 mm, Milwaukee M18 F2CHS50 50 cm
• Ryobi 36V: RY36CSX35A 35 cm, RY36CSX40D 40 cm, RY36CSX50A 50 cm
• Makita 40V XGT: UC014G 30 cm, UC016G 40 cm

Can You Put a Different Size Bar on Your Chainsaw?

Only to the lengths your saw’s maker lists. Some saws are approved for more than one: Milwaukee says its M18 FUEL 14″ and 16″ chainsaw takes both 14″ and 16″ bars and chains.

Going shorter: fit only a length your manual lists, with a chain of the matching drive-link count.

Going longer: only if the longer bar is listed for your saw. Husqvarna, for example, says its 445 II and 450 II meet the EN ISO 11681-1 chainsaw safety requirements when fitted with the guide bar and chain combinations listed in the manual.

• A length outside the listed combinations is outside the maker’s approval.

Check your manual or ask the maker which bar lengths are approved for your model.

Understanding Bar Mount Types

Bars are made for specific mounts, so a bar of the right length and pitch may still not fit your saw.

Common mount types:

• Oregon’s bar codes include a mount code — for example A041 in 160SDEA041, and Greenworks manuals list Oregon bars 100NDEA041 and 124MLEA041 — so match the mount your saw takes.

When buying a replacement bar, always verify it’s compatible with your specific saw model. Check the manual or ask the dealer.

Matching Bar to Chain: The Drive Link Connection

Here’s the critical part: when you change bar length, you must also change your chain.

Chains are sold by drive-link count (drive links are the links that run in the bar groove, not the cutting teeth). Maker examples: a 16″ / 40 cm bar takes 55 (Stihl 3/8″ P), 56 (Husqvarna 3/8″ mini, Milwaukee 3/8″ LP) or 66 (Husqvarna .325″); a 12″ / 30 cm bar takes 44–46 at 3/8″ P / LP.

Why? Oregon says a bar from one maker may take a different drive-link count from another maker’s bar of the same length, so count the links on your current chain or use the count listed for the new bar.

So if you’re upgrading from a 14-inch to a 16-inch bar, you need to:

1. Fit the new bar to your saw (if compatible).
2. Buy a new chain with the correct pitch and gauge for your new bar’s drive link count.
3. Adjust chain tension after installation.

This is why ordering the exact bar size first is important—it determines which chain you need.

Choosing the Right Bar: Decision Tree

What will you use the saw for?

• Light pruning and trimming: 10–12 inch bar. Even a battery saw works here.
• General garden work and small firewood: 14 inch bar. This is the sweet spot for home use.
• Regular firewood production or felling small trees: 16 inch bar. Worth the investment if you use it weekly.
• Professional or semi-professional work: 18–20 inch bar. Your saw’s displacement and your budget decide between these.
• Heavy-duty milling or large timber: a long bar on a saw the maker approves for it (Stihl lists bars up to 90 cm for the MS 500i and MS 660).

If you’re unsure, choose from the lengths your saw’s maker lists; we have no data on which length suits most jobs.

Watch: Video Guide

Frequently Asked Questions

What’s the longest bar I can fit on my chainsaw?

Check your manual: makers list the approved bar lengths for each model — for example 30–40 cm for the Stihl MS 170 and 300–400 mm for the Makita DUC353. We found no general add-2-inches rule in the maker sources we checked.

Will a 16-inch bar fit on a 40cc saw?

Only if the maker lists a 16-inch bar for that saw; engine size alone does not tell you. Stihl, for example, lists 30–40 cm bars for the MS 170, and Husqvarna lists 14–18 inch bars for the 235, 236 and 240.

Is a longer bar always more expensive?

Generally, yes. A longer bar requires a longer chain, which means more material and more money. A 14-inch bar might cost £20–30, while an 18-inch bar could be £40–60. Factor this in when choosing your bar length.

Can I use a 3/8-inch pitch chain on a .325-inch bar?

No. Husqvarna says the pitch must match both the drive sprocket and the guide bar; a 3/8-inch chain cannot be used with a sprocket designed for .325-inch chain.

Do battery chainsaws have shorter bar ranges than petrol saws?

Not as a rule. The battery saws we checked range from 20 cm bars (Milwaukee M18 FHS20) to 50 cm (DEWALT DCMCS575 and Milwaukee M18 F2CHS50), and Makita lists 300–400 mm for its 2 × 18V DUC353 and DUC405. Check the lengths the maker lists for your saw.

What happens if my chain is too loose on the bar?

Adjust the tension first, with the chain cool and the engine off: Oregon says the drive links should stay fully seated in the bar groove with the tie straps lightly touching the bar. If the chain cannot be tensioned correctly, check that its drive-link count matches the bar.

Should I buy a spare bar for my chainsaw?

If you use your saw regularly (more than weekly), yes. Having a second bar allows you to rotate between them while one is being sharpened or repaired. This saves downtime during busy cutting season.

Can I mix brands? (e.g., a Makita bar on a DeWalt saw?)

Only if the bar is made for your saw’s mount. Oregon’s bar codes include the mount (for example A041), and both the DEWALT DCM565 and the Milwaukee 2727-20 come with Oregon bars, so check the bar maker’s fitment list for your exact model.