Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Summary
A chainsaw chain that is too loose can leave the guide bar, and one that is too tight wears the bar and the chain and loads the drive. The job of setting it is short — power source off, chain cool, gloves on, bar nuts loosened, bar nose held up, tensioning screw turned, nuts tightened, chain pulled round by hand to check. What takes the time is doing it on a cool chain, because a warm chain shortens as it cools and a chain tensioned warm can end up too tight. This page also covers the part most people skip: a new chain stretches, so the tension you set in the shed is not the tension you have two minutes into the first cut.
What this page does not have is a number, and that is the finding rather than a gap. Every maker publishes its own test and they are not the same test: STIHL's British site describes how far the chain may lift at the middle of the bar, Husqvarna's US help centre describes how much of the drive links you should see instead of giving a measurement, EGO's manual for one battery saw gives a figure for how far the drive links of a warm chain hang out of the groove, and Oregon describes a snap test on the underside of the bar. None of them transfers to another manufacturer's saw, and no source read for this page gives a torque figure for the bar nuts at all. OSHA's own instruction is the same one this page ends on: adjust the chain tension the way the manufacturer's instructions tell you to. The FAQ below names each maker's test and says where to read it for your own machine.
Safety
READ THE MANUFACTURER DOCUMENTATION FOR YOUR SAW BEFORE YOU ADJUST THE SAW CHAIN.
This page gives no tension figure. An incorrect tension can cause serious injury.
Necessary equipment
| Item | Note |
|---|---|
| Heavy gloves | Wear heavy gloves for all work on the saw chain. |
| The wrench supplied with your chainsaw | The maker supplies one wrench for the bar nuts and the tensioning screw. |
| The manufacturer documentation for your chainsaw | The documentation gives the tension test and the tool for your saw. |
| The guide bar cover | The cover protects your hands from the saw chain between tasks. |
| Flat screwdriver optional | Some saws use a screwdriver for the tensioning screw. |
Prepare the chainsaw
Estimated 12 min to 47 min
- Read the chain tension procedure for your saw in the manufacturer documentation.5mReport a problem with step 1, Prepare the chainsaw
- Each maker gives a different test for correct tension.
- OSHA tells you to adjust the chain tension as the manufacturer instructs.
- This page gives no general figure for the tension.
- Put the saw on a firm level surface.<1mReport a problem with step 2, Prepare the chainsaw
- STIHL gives this instruction before all adjustment of the chain.
STOP THE ENGINE BEFORE YOU TOUCH THE SAW CHAIN.
STIHL tells you never to tension the chain while the engine runs. The saw chain can cut you.
- If the saw has an engine, stop the engine.<1mReport a problem with step 3, Prepare the chainsaw
- STIHL tells you never to tension the chain while the engine runs.
- If the saw has a battery, remove the battery from the saw.<1mReport a problem with step 4, Prepare the chainsaw
- EGO tells you to remove the battery before you adjust the chain tension.
- STIHL gives the same instruction for a cordless saw.
- If the saw has a power cord, disconnect the plug from the receptacle.<1mReport a problem with step 5, Prepare the chainsaw
- STIHL tells you to make sure that the saw cannot start.
LET THE SAW CHAIN BECOME COOL BEFORE YOU TOUCH IT.
The chain, the engine and the muffler are hot after use. You can burn your hand.
- Let the saw chain become cool.5mReport a problem with step 6, Prepare the chainsaw
- Husqvarna tells you to let the chain become cool before adjustment.
- A chain becomes shorter as it becomes cool.
- Oregon tells you to tension the chain only when the chain is cool.
WEAR HEAVY GLOVES BEFORE YOU TOUCH THE SAW CHAIN.
The cutters on the chain are sharp. The chain can cut your hand.
- Wear the heavy gloves.<1mReport a problem with step 7, Prepare the chainsaw
- Husqvarna tells you to wear gloves against the sharp chain.
- Keep the gloves on your hands for all work on the saw chain.
Examine the saw chain and the guide bar
Estimated 4 min to 5 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
- Release the chain brake.<1mReport a problem with step 1, Examine the saw chain and the guide bar
- The chain brake holds the saw chain.
- Husqvarna and STIHL both release the brake before the tension test.
- Read the direction to release the brake in the manufacturer documentation.
- Move the saw chain around the guide bar with the shaft of the wrench.<1mReport a problem with step 2, Examine the saw chain and the guide bar
- STIHL uses the shaft of the supplied tool in place of a hand.
- The saw chain must move freely.
- Examine the drive links in the groove of the guide bar.1mReport a problem with step 3, Examine the saw chain and the guide bar
- Oregon tells you that the drive links sit fully in the groove at the correct tension.
- A drive link out of the groove is a sign of low tension.
DO NOT USE A SAW THAT HAS A DAMAGED CHAIN.
STIHL tells you to look for a crack, a chip or a distortion. A damaged chain can break and injure you.
- Examine the saw chain and the guide bar for damage.2mReport a problem with step 4, Examine the saw chain and the guide bar
- STIHL tells you to look for a crack, a chip or a distortion.
- Look for damage on the rails of the guide bar.
- Do not adjust the tension of a damaged chain.
Set the tension of the saw chain
Estimated 7 min to 14 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
SET THE TENSION THAT THE MANUFACTURER DOCUMENTATION GIVES FOR YOUR SAW.
Husqvarna tells you that an incorrect tension can release the chain from the guide bar. A released chain can cause serious injury or death.
- Loosen the bar nuts one or two turns.1mReport a problem with step 1, Set the tension of the saw chain
- Husqvarna tells you not to remove the nuts.
- The guide bar must move a small distance.
- EGO uses a knob on the side cover in place of the nuts.
- Hold the tip of the guide bar up with one hand.<1mReport a problem with step 2, Set the tension of the saw chain
- STIHL and Husqvarna both give this instruction.
DO NOT INCREASE THE TENSION TOO MUCH.
STIHL tells you that a high tension puts a load on the parts of the saw. Damage to the guide bar and to the chain occurs.
- Turn the tensioning screw clockwise to increase the tension.2mReport a problem with step 3, Set the tension of the saw chain
- Turn the tensioning screw counterclockwise to decrease the tension.
- STIHL puts the tensioning screw at the side or at the front of the saw.
- EGO uses a knob for the same function.
- Do the tension test from the manufacturer documentation for your saw.2mReport a problem with step 4, Set the tension of the saw chain
- Each maker gives a different test for its own machines.
- This page gives no figure for the tension.
- All four makers on this page agree on two conditions.
- The saw chain must touch the underside of the guide bar.
- The saw chain must also move freely around the guide bar.
TIGHTEN THE BAR NUTS BEFORE YOU USE THE SAW.
The bar nuts hold the guide bar in position. A loose guide bar can cause serious injury.
- While you hold the tip of the guide bar up, tighten the bar nuts.1mReport a problem with step 5, Set the tension of the saw chain
- Husqvarna tightens the bar nuts with usual pressure on the wrench.
- This page gives no torque value for the bar nuts.
- EGO tightens the knob on the side cover by hand.
- Move the saw chain around the guide bar again.<1mReport a problem with step 6, Set the tension of the saw chain
- A saw chain that does not move freely is too tight.
- Decrease the tension if the saw chain does not move freely.
Do a check before you use the chainsaw
Estimated 3 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
- Do the tension test again.1mReport a problem with step 1, Do a check before you use the chainsaw
- The tension changes when you tighten the bar nuts.
- Install the cover on the guide bar.<1mReport a problem with step 2, Do a check before you use the chainsaw
- EGO tells you to install the cover on the guide bar before transport.
- Keep the gloves on your hands until the cover is in position.
- Do this procedure again after the first minutes of use of a new chain.<1mReport a problem with step 3, Do a check before you use the chainsaw
- Husqvarna tells you to do the test again after one or two minutes of work.
- EGO tells you that a new chain increases in length.
- If you set the tension of a warm chain, do this procedure again when the chain is cool.<1mReport a problem with step 4, Do a check before you use the chainsaw
- EGO tells you that a chain tensioned when warm can become too tight.
- STIHL tells you to decrease the tension again when the chain becomes cool.
- Do a check of the chain tension before each use of the saw.<1mReport a problem with step 5, Do a check before you use the chainsaw
- STIHL recommends a check of the chain tension before each use.
- OSHA tells you to do a check of the chain tension before you start the saw.
Terminology
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
- saw chain
- Also called: chainsaw chain, chain, chainsaw blade, the cutting chain, saw blade
- guide bar
- Also called: bar, chainsaw bar, blade, the metal bar the chain runs on
- chain tension
- Also called: chain tightness, chainsaw chain too loose, how tight should a chainsaw chain be, chain sag, chain adjustment
- drive link
- Also called: drive links, the tabs on the inside of the chain, chain lugs, inside teeth
- tensioning screw
- Also called: chain adjuster, tensioner, adjustment screw, tension knob, tool-less tensioner, the little screw by the bar
- bar nuts
- Also called: bar bolts, side cover nuts, clutch cover nuts, the two nuts on the side
- chain brake
- Also called: hand guard, front hand guard, brake handle, kickback brake
- combination wrench
- Also called: scrench, bar wrench, chainsaw tool, the tool that came with the saw
When to use a professional
Stop if you do not have the manufacturer documentation for your saw. This page gives no tension figure. Get the documentation from the maker of your saw. A dealer can also give the test for your model.
Stop if the saw chain or the guide bar has damage. Do not adjust the tension of a damaged chain. Do not use the saw. A dealer must examine the saw chain and the guide bar.
Stop if the tension decreases again after each adjustment. The chain, the rails of the guide bar or the tensioner can have wear. A dealer must examine these parts.
Stop if the tensioning screw does not move the guide bar. Do not use force on the screw. A dealer must repair the tensioner.
Stop if the chain brake does not operate correctly. Do not use the saw. A dealer must repair the chain brake.
This page does not tell you how to cut with a chainsaw. You must have training before you cut with a chainsaw. You must also have protective equipment. OSHA tells you to protect your head, your eyes and your ears. OSHA also tells you to protect your hands, your legs and your feet.
Common questions
How tight should a chainsaw chain be?
Tight enough that the chain sits against the underside of the bar with no sag, and loose enough that you can still pull it round by hand with a gloved hand. Beyond that there is no single number, because each maker publishes its own test and they are not the same test. STIHL's British site says the chain should not lift more than around 5 mm when you lift the top of it at the middle of the bar. Husqvarna's US help centre gives no measurement at all and instead says you should see only a small part of the drive links when you lift the chain, without pulling them fully out of the groove. EGO's manual for the CS1400 battery saw says a correctly tensioned warm chain will have its drive links hanging approximately 0.050 in (1.3 mm) out of the bar groove, which is a figure for that saw and not a rule for yours. Oregon describes a snap test: pull the chain down on the underside of the bar until one or two drive links come clear, let go, and it should snap straight back.
What torque do the bar nuts need?
No source read for this page publishes one, which is why there is no figure in the specifications above. Husqvarna's instruction is to tighten both nuts firmly with normal wrench pressure while you hold the nose of the bar up. STIHL says to tighten the fixing nut or nuts with the tool supplied with the saw. EGO's battery saw does not use nuts at all on the model read here — the side cover is held by a knob that is tightened by hand. If your own manual gives a torque figure, use that figure and ignore this paragraph.
Why does my chainsaw chain keep coming loose?
A new chain stretches, and that is normal rather than a fault. Husqvarna's guidance is to check and adjust the tension again after one or two minutes of cutting on a new or recently adjusted chain, and EGO's manual says outright that new chains tend to stretch and should be checked frequently. Heat is the other half of it: the chain expands as it warms up in use and shortens again as it cools. If the chain still goes slack after every adjustment on a chain that is well past its first few cuts, the chain, the bar rails or the tensioner may be worn, and that is a job for a dealer rather than another turn of the screw.
Can I tighten the chain while the saw is still hot?
Better not to, and both STIHL and Oregon say so for the same reason. A warm chain has expanded, so a chain you tension while it is warm can be too tight once it cools, and an over-tight chain loads the drive and wears the bar and chain. STIHL's own wording is that if you do tension at operating temperature you must remember to reduce the tension again once the saw has cooled. There is a burn risk too — the engine and muffler of a petrol saw stay hot long after the cut. If you cannot wait, set it warm, then check it again cold before the saw goes back to work.
Which way do I turn the chainsaw chain tensioner?
Clockwise tightens and counter-clockwise loosens, on the Husqvarna and STIHL instructions read for this page. Where the screw is varies: Husqvarna describes front tensioners, side tensioners and tool-less dials, and says all three do the same job. The part people miss is holding the nose of the bar up while you tension and while you tighten the nuts, which both makers ask for. Without that, the bar settles under the chain afterwards and the chain you set snug goes slack.
My chainsaw chain came off the bar — what does that mean?
Most often it means the chain was too loose, and it is the failure this whole page exists to prevent. Husqvarna's own warning is blunt: a saw chain with incorrect tension can come loose from the guide bar and cause serious injury or death. Oregon adds that a loose chain also increases the risk of kickback. Before you refit and re-tension, look at the chain and the bar for damage, because a chain that has been thrown often is not fit to go back on. If the bar rails are damaged or the chain is bent, cracked or chipped, take it to a dealer instead.
Do I really have to take the battery out first?
Yes, and it takes five seconds. EGO's instruction for the CS1400 is to stop the motor and remove the battery pack before adjusting the chain tension. STIHL says the same thing more generally: for a cordless or electric saw, take the measures needed to make sure it cannot start, meaning remove the battery or disconnect the plug. For a petrol saw the equivalent is that the engine must not be running — STIHL's wording is never to check or tighten the chain while the engine is running. Your hands are going to be on a set of sharpened cutters, so the machine gets no chance to start.
Is there a way to check the tension without touching the chain?
Partly, yes. STIHL suggests using the shaft of the combination tool supplied with the saw to pull the chain round instead of your fingers, which keeps your hand off the cutters. You still want gloves on, because checking the sag and the drive links means working close to the chain either way. Nothing about the check needs the saw to be running, so if a video shows someone testing tension on a running saw, ignore it.
Related procedures
- Replace a chainsaw guide bar and check whether the drive sprocket is worn too
- What chain fits my chainsaw? How to check pitch, gauge, and drive link count
- Sharpen a chainsaw chain with a round file and a depth gauge, and know when to stop filing
- How to change the blade on a lawn edger
- What size blade fits my circular saw, and does the RPM rating on the blade matter?
- How to put new line in a string trimmer, and what size line to use
- Why a leaf blower loses power, and how to clear a blocked intake
- What NRR do I need for ear protection with power tools and a lawn mower?
Sources
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
- Tier 1How to: adjust the tension of the saw chain — Petrol Chainsaw support
- Tier 1How to: adjust the tension of the saw chain — Battery Chainsaw support
- Tier 1How to tighten your chainsaw chain
- Tier 1Tightening Chainsaw Chain
- Tier 1Operator's Manual — 56V Lithium-Ion Cordless 14 in. Chain Saw (CS1400 / CS1400-FC)
- Tier 1QuickCard: Chainsaw Safety (OSHA 3269-04R 2013)
Revision history
Current version 1 · updated 2026-07-29 · next review due 2027-07-29
- v1 · 2026-07-29First draft. Scope is petrol, battery and corded electric chainsaws with a bar-nut or tool-less tensioner. The page publishes the method and no tension figure: STIHL GB, Husqvarna US, EGO and Oregon each publish a different test for their own machines, none of them transfers between makers, and no source read for this page publishes a bar nut torque at all. Correct tension, bar nut torque, chain-to-bar clearance, warm-chain drive link position and chain pitch all publish as consult-manufacturer. The per-maker figures that exist are named and attributed in the FAQ as the evidence for that refusal, never presented as a value for the reader's own saw. OSHA 3269 QuickCard carries the governing instruction — chain tension is adjusted according to the manufacturer's instructions. Two STIHL USA URLs were checked and not used: the chain tension video page returned 404, and the Sharp Advice saw chain and guide bar PDF resolved 200 but carries no extractable text layer, so nothing could be read from it.
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Comments and corrections
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.