What Size Chainsaw Do I Need? A Bar Length Guide for Homeowners

The right chainsaw size matches the wood you cut: that means 8 to 15 inches for light work and 16 to 20 inches only if you cut thick limbs and trunks often. Bigger is not better, because a larger saw is heavier, and weight tires you before the work is done. On my 3.7-acre apricot and plum orchard a chainsaw is the tool I reach for last, so I size one for the few big cuts, not for the average day. Below you get sizes by job, how to measure a bar, why the number on the box overstates your cut, and which jobs are too big for any homeowner saw.

What Size Chainsaw Do I Need? The Short Answer by Job

Size the saw to the thickest wood you cut often, then stop. Alabama Extension gives three bands: a lightweight saw with a 8 to 15 inch bar for light work such as small limbs and small trees, a midweight saw with a 16 to 20 inch bar for frequent cutting of thick limbs and trunks, and bars over 20 inches, which are typically professional grade and not recommended for homeowners. NC State Extension adds that it is unlikely you will need a bar longer than 16 inches for most common household uses. My mini against full size chainsaw comparison explains the differences in cutting limits, weight and safety.

On my land the answer sits at the low end. Loppers and a hand saw handle most of the pruning on live fruit wood, so the chainsaw only sees dead apricot and plum wood, a few hedgerow stems and the odd storm limb. I buy for the thickest piece of dead wood I expect to cut, never for the one dramatic job. I rank cordless pruning saws for yard branch work in my best mini chainsaw picks.

How to Measure Chainsaw Bar Length

Measuring takes a tape measure and a minute, but the saw has to be fully off and made safe first, because your hands go next to the chain.

1. Make the saw safe as described above.
2. Lay the tape along the bar, starting at the front tip.
3. Run it all the way back to the cutter closest to the body of the saw.
4. Round the result to the nearest inch.
5. Compare it with the number etched on the bar and the figure in the manual.

That is the method University of Georgia Extension gives for chainsaw bar length: from the front tip to the cutter closest to the body, rounded to the nearest inch.

Read the Number Off the Saw

The manual states the bar size your saw is built for, and the same number is etched into the bar. Alabama Extension says to check the owner’s manual for the chainsaw guide bar length that suits your specific saw before you change it. A bar that is not listed for your saw can also change how the saw behaves, so I treat the manual’s list as the limit, not the starting point. Drive link thickness is another number that has to match, and my guide on what chainsaw gauge means explains it.

Called Length Versus Cutting Length

The number you measure is the called length, and it is longer than the wood a saw cuts through in one pass. According to Makita’s manual for its corded saws, a 16 inch bar has a cutting length of 14 inches, and a 14 inch bar has a cutting length of 12-5/8 inches. Size the saw to the cutting length, not to the number on the box.

A Worked Example With a 10 Inch Round

Say the thickest dead limb you cut is 10 inches across. Oregon State University Extension says the bar should be as long as the diameter of the largest tree you will cut, and University of Georgia Extension says slightly longer. A saw with a 14 inch cutting length clears that round with 4 inches to spare, and one with 12-5/8 inches clears it with 2-5/8 inches to spare.

Measure across the thickest piece with a tape before you pick a bar, not after the saw is in the cart. I do that every time, because a round of apricot trunk looks smaller on the ground than it is. When the round is small enough for a hand tool, my chainsaw and axe guide shows which tool fits which job.

Match the Bar to the Log or Limb

Two extension sources give a rule for pairing the bar with the wood, and they differ a little. Choose a bar whose cutting length clears the thickest wood you cut, and keep a margin. For higher branches, I discuss bar length, branch size and weight in my guide titled “what size pole saw do I need”.

Two Sourced Rules

• Oregon State University Extension: the bar is as long as the diameter of the largest tree you will cut.
• University of Georgia Extension: the saw has a bar slightly longer than the diameter of the tree, an engine powerful enough for the job and a sharp chain in good repair.

An older University of Wisconsin Extension guide adds the limit: buy the shortest bar that meets your cutting needs, because injury risk grows with bar length.

When the Wood Is Wider Than the Bar

Some saw manuals describe a technique for wood wider than the bar. It is a trained technique, and I do not teach it here. For a beginner, wood wider than the bar is a reason to stop and call a professional.

Why Bigger Is Not Better

A longer bar brings a bigger, heavier saw, and weight costs control. Alabama Extension puts it directly: the larger the saw, the heavier it gets and the greater the risk of increasing user fatigue and injury later in the day. It also says modern saws are powerful, and a smaller saw is often all you need for jobs around the yard or farm. My homeowner’s guide on horsepower a chainsaw needs covers the power side of that choice.

NC State Extension makes the same point for buyers: if your jobs are storm cleanup, small trees or large shrubs, and firewood, you do not need a professional-grade chainsaw. You need an easy-starting engine and basic safety features. A saw that feels light at minute five feels heavy at minute thirty, and that is when I notice my cuts getting careless. The compact saws I rank for limbs and small logs are in my lightweight chainsaw roundup.

Weight and Vibration

NC State Extension notes that weight varies with the size of the saw, but vibration is what really tires you out. In a study of groundskeepers in the southeastern United States, chainsaws gave the highest hand vibration of the tools measured, about 8 meters per second squared at the right hand, against less than 2 for riding mowers and handheld blowers (1). Take breaks, and stop if your hands tingle or go numb. If it persists, see a doctor.

I plan wood work in short sessions with the saw off between them. Dense, dry stone-fruit wood dulls a chain quickly, and fine dust instead of chips tells me to stop and sharpen before I push harder.

Power Source Changes the Size Question

Bar length alone does not tell you how much power a saw has or whether it suits long cutting sessions, and the power source shifts which size is sensible. NC State Extension says a battery or electric saw has less power, increases the time you spend cutting and is not designed for prolonged use or for cutting large material. It calls them great for small, infrequent tree and shrub projects, and adds that electric saws often have only 100 feet of cord. I explain battery platforms and volts in my guide on what voltage chainsaw you need.

So a battery saw with a short bar fits a few pruning cuts near the house, and a gas saw suits long sessions with thicker wood. My battery against gas chainsaw comparison covers the choice between the two, and volts, engine cc and horsepower have their own pages. Here the rule stays the same for all of them: pick the shortest bar that clears your wood. Alabama Extension also says a battery saw is just as dangerous as its gas counterpart.

Jobs That Are Too Big for a Homeowner Saw

Some jobs stay beyond a homeowner saw at any bar length. A bigger saw does not make them safe; it makes a mistake costlier.

According to Alabama Extension, the distance to keep is at least 10 feet from distribution lines and 33 feet from energized trees. Felling is the most dangerous chainsaw job. Never work alone, keep everyone at least two tree lengths away, and plan and clear two escape routes angled back from the direction of fall before any felling cut. Never cut at or above shoulder height, and never cut from a ladder or a roof.

After a storm I cut what lies on the ground and leave what hangs or is bent under tension to a crew. I mark the drip line with stakes before I cut anywhere near the irrigation, and I keep someone within earshot.

Training and Gear Matter More Than Size

No bar length makes a saw safe. Training, protective gear and a working technique do more than any size choice, and the injury data shows who gets hurt.

What the Injury Data Shows

US emergency department data for 2006 to 2016 show that power saws caused 89 percent of 18,250 saw and axe injuries, mostly lacerations to the fingers and hand, and most happened at home (2). A series of 185 patients with non-occupational chainsaw injuries in rural areas found leg injuries in 109 and arm injuries in 76, and the arm injuries cost more lost work, 75 days against 60 (3). An Irish survey of 62 domestic chainsaw accidents found that only 3 percent of the injured users wore any protective gear (4).

Kickback and Control

Kickback is the main reason to respect the tip of the bar. If the upper part of the bar tip touches wood or another object, the bar can kick back up and toward you (rotational kickback). Wood pinching the chain on the top of the bar pushes the saw straight back at you (pushback), and wood pinching the bottom pulls it forward, away from you (pull-in).

Laboratory tests found that chain tension, anti-kickback chain links, guide bars with sliding ends and a quick chain brake influence kickback (5), and that kickback risk depends on the wood being cut and on where the bar tip contacts it (6). According to Husqvarna, a smaller bar tip radius decreases the force of a kickback. A low-kickback chain, a chain brake and a correct grip reduce these risks; none removes them.

Gear and Training

Wear impact-rated safety glasses with side protection marked Z87+ (a mesh face screen adds to them but never replaces them), hearing protection, chainsaw chaps or chainsaw trousers used within their maker’s stated limits (some are not designed to stop a battery or corded saw’s chain, and no clothing guarantees protection), work gloves and sturdy boots with ankle support, plus a hard hat when you fell a tree or anything can fall from above. Hold the saw with both hands, right hand on the rear handle and left hand on the front handle, thumbs and fingers wrapped around the handles, with your body to the left of the chain line and firm footing.

Before each use, inspect the saw as its manual describes: test the chain brake by the manual’s method, and check the throttle trigger lockout, the stop switch, the chain catcher, the guards and the chain’s sharpness, tension and condition; on a gas saw the chain must not move at idle. If any check fails, do not use the saw until it is repaired, and never disable a safety device.

Read the manual and get hands-on training before the first cut. Clemson recommends professional training for working with chainsaws. A beginner starts with small, simple cuts of wood lying on the ground, never with felling. I wear ear protection even on a battery saw, because quieter does not mean quiet.

Start Small and Let the Wood Set the Size

Three things decide the size: the thickest wood you cut regularly, the cutting length of the bar, and the weight you can control for a full session. Take the thickest dead branch you cut each year, measure it, and choose the shortest bar that clears it with room to spare. On my land that means a small saw, and a lift onto a stand for logs so the chain stays out of the dirt. Every saw in my roundup of the best chainsaw picks for homeowners has a chain brake for yard cleanup.

If a job needs more than the saw and your training allow, hire the professional. Choosing the right chainsaw size means matching the tool to the wood in front of you. Once the size is settled, my best chainsaw picks for 2026 rank battery, gas and corded saws.

Frequently Asked Questions

How thick of a tree can a 12 inch chainsaw cut?

A 12 inch chainsaw cuts through wood that is thinner than 12 inches, because the cutting length is shorter than the called length. In one maker’s manual a 14 inch bar has a cutting length of 12-5/8 inches. Keep to wood clearly thinner than the cutting length, and leave thick trunks to someone trained.

What size chainsaw do I need to cut firewood?

A saw for firewood needs a bar that clears the thickest piece you cut, and Alabama Extension puts frequent cutting of thick limbs and trunks at a 16 to 20 inch bar. NC State Extension says most household uses rarely need more than 16 inches. Measure your thickest round first and pick the shortest bar that clears it.

How do you measure the length of a chainsaw bar?

You measure the length of a chainsaw bar from the front tip back to the cutter closest to the body of the saw, then round to the nearest inch. Make the saw safe first: release the trigger, engage the chain brake (on a battery or corded saw, if it has a brake lever), switch the engine or motor off and wait until the chain has stopped; then on a gas saw let the engine and muffler cool and pull the spark plug cap off, on a battery saw take the battery out, and on a corded saw pull the plug from the outlet by the plug, not the cord, and put on gloves before touching the chain, and release the chain brake only when the exact manual’s procedure requires it. The same number is etched on the bar and listed in the manual.

Should I get a 20 or 24 inch chainsaw?

For most homeowners a 20 inch chainsaw is the top of the sensible range, and a 24 inch saw is more than the job needs. Alabama Extension calls bars over 20 inches typically professional grade and not recommended for homeowners. A bigger saw also weighs more, which adds fatigue and risk.

What size chainsaw do I need for big trees?

Big trees need a certified arborist or a professional crew, not a bigger homeowner saw. Large, leaning, dead or hung trees, and trunks or limbs under tension, are beyond a homeowner job at any bar length. Treat every downed power line, and anything touching it, as live: stay well away and call the utility, and leave work near a power line to its qualified line-clearance crews, because a general arborist is not automatically qualified for it.

References

1. Chen N, Yang S, Oh J. Evaluation of hand-arm vibration (HAV) exposure among groundskeepers in the southeastern United States. Annals of Work Exposures and Health. 2025;69(1):81-95.
2. Sritharen Y, Hernandez MC, Zielinski MD, Aho JM. Weekend woodsmen: overview and comparison of injury patterns associated with power saw and axe utilization in the United States. Am J Emerg Med. 2018;36(5):846-850.
3. Özdeş HU, Ergen E, Köroğlu M, et al. Chainsaw-related extremity injuries. Medicina (Kaunas). 2025;61(4):759.
4. Doyle YG, Conroy RM. Prevention of timber felling and chainsaw-related accidents in the Republic of Ireland. Accid Anal Prev. 1989;21(6):529-534.
5. Dąbrowski A. Reducing kickback of portable combustion chain saws and related injury risks: laboratory tests and deductions. Int J Occup Saf Ergon. 2012;18(3):399-417.
6. Dąbrowski A. Kickback risk of portable chainsaws while cutting wood of different properties: laboratory tests and deductions. Int J Occup Saf Ergon. 2015;21(4):512-523.

Safety Note: Read your saw’s manual first and get hands-on training before your first cut. A chainsaw can react faster than you can: if the upper part of the bar tip touches wood or another object, the bar can kick back up and toward you; wood pinching the top of the chain can push the saw straight back at you, and wood pinching the bottom can pull it forward. Keep the bar tip out of contact and watch for wood closing on the bar. A low-kickback chain and a chain brake reduce these risks but never remove them. Before each use, inspect the saw as your manual describes: test the chain brake, and check the throttle lockout, the stop switch, the chain catcher, the guards and the chain. On a gas saw the chain must not move at idle. If any check fails or a part is missing or damaged, do not use the saw until it is repaired, and never disable a safety device. Wear impact-rated safety glasses with side protection marked Z87+ (a mesh face screen adds to them but does not replace them), hearing protection, chainsaw chaps or chainsaw trousers, work gloves and sturdy boots with ankle support, and a hard hat when you fell a tree or when anything can fall from above. Use leg protection within its maker’s stated limits: some chaps are not designed to stop the chain of a battery or corded saw, and no clothing guarantees protection. Hold the saw with both hands, right hand on the rear handle and left hand on the front handle, thumbs and fingers wrapped around the handles, and keep your body to the left of the chain line with firm footing. Never cut one-handed with a rear-handle saw, never cut at or above shoulder height, and never cut from a ladder or a roof. Top-handle saws are made for trained tree workers: follow that saw’s manual. Keep children, bystanders and pets well away while you cut. Never work alone. Start a gas saw with the chain brake engaged, on the ground or held firmly as the manual shows, never by drop-starting it, and at least 10 feet from where you fuelled it. Refuel outdoors with the engine off and cool, with no smoking, flames or sparks nearby, wipe up spills, and use only the fuel mix and ethanol content your manual allows. Exhaust contains carbon monoxide, which can kill: never run a gas saw indoors or in a garage, shed or other enclosed space. Before you touch the chain, clear a jam, adjust the tension or sharpen: release the trigger, engage the chain brake, stop the engine or motor and wait until the chain has stopped. Then, on a gas saw, let the engine and muffler cool and pull the spark plug cap off; on a battery saw, take the battery out; on a corded saw, unplug it by the plug. Put on gloves before you touch the chain, and release the chain brake only when your manual’s procedure calls for it. To carry the saw, stop it, take out the battery or unplug it, keep the chain brake engaged and the bar pointing behind you, and fit the bar cover for transport. Use a corded saw only with an outdoor-rated extension cord of the gauge your manual gives, plugged into GFCI-protected power. Never use it in rain or wet conditions: GFCI protection does not make that safe. Keep the cord away from the chain. Use only the chains and bars your manual approves. Felling trees is the most dangerous chainsaw job. Before any felling cut, keep everyone at least two tree lengths away, and plan and clear two escape routes angled back from the direction of fall; when the tree starts to fall, follow your manual’s retreat steps (release the trigger, stop the saw and set it down as it describes) and move away along that route; never delay escape to cool, unplug or cover the saw. A large, leaning, dead or hung-up tree, a trunk or limb under tension after a storm, and any tree near a house or a road are jobs for a certified arborist. Power lines are a separate danger: treat every downed line, and anything touching it, as live, stay well away and call the utility; before any work near a power line, contact the utility and leave that work to its qualified line-clearance crews. Stop when you are tired, and take breaks if your hands tingle or go numb.