Review Information
- Reviewed by: Jack Beurge
- Review type: Research-based review
- Testing status: Not personally tested by SAWOFF — based on manufacturer documentation, reputable sources, and documented owner-reported patterns
- Published: October 19, 2026
- Sources: Oregon Tool guide bar and saw chain sizing and replacement documentation · STIHL and Husqvarna owner's manuals and bar and chain fitment charts · ANSI B175.1 chainsaw safety standard (bar and chain guarding requirements)
Information in this review is labeled as one of four types: 🧪 SAWOFF hands-on test, 🏭 manufacturer specification, 📚 research from reputable sources (including documented owner-reported patterns), or 🧠 editorial assessment. See our testing methodology and editorial policy.
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QUICK ANSWER
Measure bar length from the tip of the bar back to where the bar enters the saw housing, then round up to the nearest even inch. That is the called length - the number on every spec sheet and the one you use when buying a bar. Measure a chain by counting drive links and matching pitch and gauge, never by the bar’s inch size. A 20-inch bar from one brand can take 72 drive links while another takes 81, so the inch number alone cannot identify a chain.
Bar Length vs Chain Length: Two Different Measurements
These two measurements get mixed up constantly, and the confusion is expensive: it is how people end up with a chain that is four links too short or too long and a saw they cannot use.
- Bar length answers “how big is the cutting tool?” It is a distance in inches measured on the bar itself, and it mostly decides what diameter wood the saw can buck in one pass.
- Chain length answers “which loop fits this bar and sprocket?” It is a count of drive links, plus two fitment numbers (pitch and gauge). It does not describe cutting capacity at all.
A chain is a closed loop, so its “length” is really link count. Bar length is an exposed distance. Keeping that split in your head is the whole trick, and the rest of this guide is the procedure.
Why Your Tape Measure Reads Two Different Numbers
Bars carry two lengths, and the one you need depends on the job:
| Measurement | What it measures | Typical use |
|---|---|---|
| Called length (cutting length) | Tip of the bar to the point where the bar exits the saw housing | Buying a bar, matching a saw to wood, every spec chart |
| True length (overall length) | Entire bar from tip to tail, measured off the saw, no rounding | Ordering an exact replacement or confirming a bar number |
Called length is the advertised number. A bar sold as “20 inches” typically measures 20 to 20.5 inches from tip to housing when new, because manufacturers build in a little margin for wear. True length on the same bar is about 23 to 24 inches, because the tail - with its oil holes, mounting slot, and tensioner slot - hides inside the clutch cover.
| Called length | Typical true length |
|---|---|
| 14 in | 17-18 in |
| 16 in | 19-20 in |
| 18 in | 21-22 in |
| 20 in | 23-24 in |
| 24 in | 27-29 in |
If someone tells you their “18-inch bar measures 21 inches,” they measured true length. Both are correct; only called length goes in a bar shopping cart.
How to Measure a Chainsaw Bar Length
The mounted method takes about 30 seconds and needs no tools. The one rule that matters: start at the bar tip, stop at the housing, and measure along the bar’s centerline rather than angling across the nose.
Rounding Chart: Tape Reading to Bar Size
| Tape reading (tip to housing) | Bar size you have |
|---|---|
| 13.5-14.5 in | 14 in |
| 15.5-16.5 in | 16 in |
| 17.5-18.5 in | 18 in |
| 19.5-20.5 in | 20 in |
| 23.5-24.5 in | 24 in |
A bar that reads slightly over its called size is normal, especially when new. A bar that reads clearly under its label has either been shortened by damage or was never the size you thought - check the stamp before ordering.
Reading the Bar Stamp
Most bars carry their own specification near the tail, and it saves you the measuring entirely. A typical stamp looks like:
3/8 .050 72DL
That reads as 3/8-inch pitch, .050-inch gauge, 72 drive links. Some bars also stamp the called length (18, 20, 24) and a manufacturer bar code. If the stamp is worn or painted over, the owner’s manual lists the factory bar and chain combination for your model.
How to Measure a Chainsaw Chain Length
Chain length is a drive link count. The drive links are the pointed tabs on the inside of the loop that sit down in the bar groove and engage the sprocket - not the flat tie straps between cutters.
Method 1: Count Drive Links (Exact)
This is the only method that never lies. Lay the chain straight, count each drive link once around the loop, and write the number down. A used chain that has been run hard may measure slightly longer than new, but the link count does not change - which is exactly why shops ask for it instead of a length in inches.
If you are buying a pre-made loop, the count needs to match exactly. If you are having a shop spin a custom loop from bulk chain, one link either way is usually correctable, but match the count whenever you can.
Method 2: Estimate From the Laid-Out Length
You can estimate the link count without counting, and it is useful for a sanity check:
- Lay the chain flat and straight, pulled taut.
- Measure the overall length in inches.
- Divide by the pitch (0.375 for 3/8, 0.325 for .325, 0.404 for .404).
- Round to the nearest whole number.
The result lands within a link or two of the true count if the chain is in good shape and truly straight. Treat it as a cross-check, not as the number you order by.
Method 3: Read the Bar Stamp (Fastest)
Pitch, gauge, and drive links stamped on the bar tail are the authoritative spec, and they describe the chain the bar was designed for. If your bar has a stamp like “3/8 .050 72DL,” that is the chain to buy - assuming the bar has not been swapped for something nonstandard.
Typical Drive Link Counts by Bar Length
Use this table to recognize an answer that looks wrong. The ranges are wide on purpose: the same bar length can carry different link counts across brands, pitches, and sprocket sizes.
| Bar length (called) | Typical drive links | Anchors worth knowing |
|---|---|---|
| 10-12 in | 40-50 | Mini and battery saws on 3/8 low profile |
| 14 in | 50-56 | Worx WG384 14-inch: 52 links on 3/8 low profile, .043 |
| 16 in | 55-68 | STIHL MS 170 16-inch: 55 links on 3/8 Picco, .043; .325 bars commonly 66-67 |
| 18 in | 60-74 | Homeowner .325 and 3/8 bars cluster in the low 60s to low 70s |
| 20 in | 66-81 | Oregon 3/8 .050 frequently 72; STIHL 3/8 frequently 81 |
| 24 in | 80-92 | 3/8 .050 pro bars commonly 84-88 |
| 28-36 in | 91-123+ | .404 logging bars climb past 100 links |
The lesson in that table is the 20-inch row. Two bars with the same called length can differ by 15 drive links, so “I need a 20-inch chain” is not an order anyone can fill correctly. Give the seller pitch, gauge, and link count.
Pitch and Gauge: The Other Two Numbers
Pitch and gauge are independent of bar length, and both must match or the chain will not run correctly.
Pitch is the spacing of the chain’s links. Measure the distance from the center of one drive link to the center of the third drive link, then divide by two:
| Pitch | Span across 3 drive links | Typical saws |
|---|---|---|
| 1/4 in | 0.50 in | Mini saws and carving bars |
| .325 in | 0.65 in | 40-60cc mid-range saws |
| 3/8 in low profile | 0.75 in | Homeowner electric and small gas saws |
| 3/8 in standard | 0.75 in | Pro saws from 50-90cc |
| .404 in | 0.81 in | 90cc and up logging saws |
Note that 3/8 low profile and standard 3/8 share the same pitch but are not interchangeable - the cutters and usually the gauge differ. If you are unsure which you have, the bar stamp settles it.
Gauge is the thickness of the drive link where it fits in the bar groove. Measure the link tail with a caliper, or drop it into the groove and feel for side play. Common gauges are .043, .050, .058, and .063 inch. A chain with too thin a gauge leans in the groove and cuts crooked; too thick and it will not seat at all.
For the full breakdown of how pitch, gauge, and cutter profiles interact, see our chain size chart and the complete chain guide.
What to Order Once You Have the Numbers
For a chain, you need three numbers:
- Pitch (such as .325 or 3/8)
- Gauge (such as .050 or .063)
- Drive link count (such as 72)
For a bar, add:
- Called length (such as 18 inches)
- Bar mount pattern (STIHL, Husqvarna, Oregon, or a model-specific mount)
- Nose sprocket tooth count, if the listing asks for it
Write all of it down before you open a browser or walk into a shop. A phone photo of the bar stamp is the fastest backup, and it resolves most counter arguments in seconds. If you are replacing a whole cutting assembly rather than one part, our chain replacement guide walks through the matching process step by step.
Common Measuring Mistakes
| Mistake | What it does | Fix |
|---|---|---|
| Measuring from the back of the saw or the bar studs | Adds 2-4 inches and orders an oversized bar | Start at the point where the bar exits the housing |
| Calling the full bar length the bar size | Orders a bar 3-4 inches too long | Called length is tip to housing; true length is for exact replacement only |
| Buying a chain by bar inches | A 20-inch bar can take 66-81 links depending on brand | Count drive links and match pitch and gauge |
| Counting tie straps instead of drive links | Gives roughly half the correct count | Count the tabs that ride inside the bar groove |
| Confusing pitch with gauge | Chain will not seat, or leans and cuts crooked | Pitch is link spacing; gauge is drive link thickness |
| Measuring a damaged or shortened tip | Reports a size that never existed | Check the stamp and the owner’s manual before trusting the tape |
| Rounding down to the nearest inch | Finds a bar size that is not made | Bars come in 2-inch steps; round up to the nearest even number |
The first two mistakes cause most wrong orders, and both come from the same misunderstanding: the called length stops at the housing, not at the end of the metal. Once that clicks, the tape measure stops arguing with the label.
FAQ
How do you measure a chainsaw bar length?
Measure from the tip of the bar back to the point where the bar enters the saw housing, then round up to the nearest even inch. A reading of 18.5 inches is a 20-inch bar. That is the called length, and it is the number manufacturers use.
What is the difference between called length and true length?
Called length is the exposed cutting length from tip to powerhead and is what every spec chart lists. True length is the entire bar measured end to end after removal, and it runs about 3 to 4 inches longer because the tail sits inside the clutch cover.
How do you measure a chainsaw chain length?
Count the drive links - the tabs on the inside of the loop that ride in the bar groove. Chain length is not sold in inches because link counts vary by brand, pitch, and sprocket size even at the same bar length. Count the loop or read the count from the bar stamp.
How many drive links are on a 16-inch chainsaw chain?
Most 16-inch setups run 55 to 68 drive links. A STIHL 16-inch 3/8 Picco bar takes 55, while a 16-inch .325 bar typically takes 66 to 67. The bar length alone does not determine the count, so verify against the old chain or the bar stamp.
Can I measure a chainsaw chain with a tape measure?
You can estimate the link count: lay the chain flat and straight, measure the length, and divide by the pitch. The result is usually within a link or two. For an exact order, count the drive links instead - worn or kinked chains make the tape method unreliable.
How do I know what chain fits my saw without removing the old one?
Read the stamp on the bar tail, near the mounting slot. It usually shows pitch, gauge, and often the drive link count, such as 3/8 .050 72DL. If the stamp is worn, the owner’s manual lists the factory bar and chain combination for your model.
Does a longer bar take a longer chain?
Yes, but only in drive link count. A longer bar needs more links to wrap around it, while pitch and gauge stay the same for that bar family. That is why a “20-inch chain” is not a universal part - the link count is what makes it fit.
Keep Reading
- What Size Chainsaw Do I Need? Bar Length Guide - match bar length to the wood you cut.
- Chainsaw Size Guide - how bar, power, and weight work together.
- Chainsaw Chain Size Chart - pitch, gauge, and drive links in detail.
- Chainsaw Chain Guide - fitment, cutter profiles, and replacement.
- Chainsaw Chain Replacement - swap a chain without guessing.
The Ultimate Chainsaw Maintenance Field Toolkit
The complete 96-page printable manual. Avoid costly $400 repairs, master 30°/35°/10° chain sharpening angles, and clear flooded engines in 30 seconds.
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Frequently Asked Questions
How do you measure a chainsaw bar length?
Measure from the very tip of the bar back to the point where the bar enters the saw housing. That is the called (cutting) length, and it is the number printed on the label. Round up to the nearest even inch: a bar that measures 18.5 inches is sold as a 20-inch bar.
What is the difference between called length and true length?
Called length is the exposed cutting length from tip to powerhead, and it is what manufacturers advertise. True length is the entire bar measured end to end after removal, and it runs about 3 to 4 inches longer because the tail sits inside the clutch cover.
How do you measure a chainsaw chain length?
Count the drive links - the tabs on the inside of the loop that ride in the bar groove. Chain length in inches is not a standard size, because two 20-inch bars from different brands can take 68 to 81 drive links. Count the links or read the count stamped on the bar tail.
How many drive links are on a 16-inch chainsaw chain?
Most 16-inch setups use 55 to 68 drive links, because the count depends on pitch, gauge, and the bar maker. A STIHL 16-inch 3/8 Picco bar takes 55 links, while a 16-inch .325 bar commonly runs 66 to 67. Count the old chain or read the bar stamp instead of trusting the bar length.
Can I measure a chainsaw chain with a tape measure?
You can estimate it. Lay the chain flat in a straight line, measure the length, and divide by the pitch. That gives an approximate link count, but the measurement is easy to get wrong on a worn loop. Counting drive links takes an extra minute and is exact.
How do I know what chain fits my saw without removing the old one?
Read the stamp on the bar tail, near the mounting slot. It usually shows pitch, gauge, and often the drive link count, for example 3/8 .050 72DL. If the stamp is worn, check the owner's manual for the bar and chain combination that shipped with the saw.
Does a longer bar take a longer chain?
Yes, but only in drive link count. A longer bar needs more links to wrap around it, while pitch and gauge stay the same for a given bar family. That is why you cannot buy a 20-inch chain and assume it fits every 20-inch bar.
