Most handheld belt sanders take 3" x 18", 3" x 21", 3" x 24", 4" x 24" or 4" x 36". Most benchtop belt/disc combos take 1" x 30", 2" x 42", 4" x 36" or 6" x 48". Knife grinders take 2" x 72". If you know your machine's make and model, find it in the chart below — every row is sourced to a manufacturer page, manual or retailer listing, and anything we could not confirm is marked as unverified rather than guessed.
Belt size is always written width x length, in inches, and both numbers matter. Width is set by the platen and the crown of the drive wheel. Length is set by how far the tensioner travels — which is why a 3x21 sander will not run a 3x24 belt even though the width is right.
Three ways to identify your belt size
1. Look at the belt already on the machine. Nearly every abrasive belt is printed on the cloth backing with the maker, the grit, and the size. It is usually on the inside of the belt, running along the splice.
2. Look at the machine. Handheld sanders almost always have the belt size cast or stickered on the housing, and it is usually in the model name (Makita 9403 is sold as a "4 x 24 Belt Sander"). Benchtop combos name the size in the model description: a Rikon 50-112 is a 4x36, a 50-120 is a 6x48.
3. Look it up below. The chart is organized by machine type, then brand.
Sanding belt size chart by machine make and model
Handheld and portable belt sanders
| Brand | Model | Belt size | Verified |
|---|---|---|---|
| Makita | 9403 | 4" x 24" | Yes — makitatools.com/products/details/9403 |
| Makita | 9404 (variable speed) | 4" x 24" | Yes — makitatools.com/products/details/9404 |
| Makita | 9903 | 3" x 21" | Yes — makitatools.com/products/details/9903 |
| Makita | 9924DB | 3" x 24" | Yes — makitatools.com/products/details/9924DB |
| Makita | 9911 / 9911KX1 | 3" x 18" | Yes — Northern Tool |
| Makita | 9031 (file sander) | 1-1/8" x 21" | Yes — makitatools.com/products/details/9031 |
| Makita | 9032 (file sander) | 3/8" x 21" | Yes — makitatools.com/products/details/9032 |
| DeWalt | DW433 | 3" x 21" | Yes — Northern Tool |
| DeWalt | DWP352VS | 3" x 21" | Yes — eReplacementParts |
| Bosch | 1274DVS | 3" x 21" | Yes — Fine Woodworking |
| Bosch | GBS 75 AE / PBS 75 A (75 x 533 mm) | 3" x 21" | Yes — RS Components |
| Milwaukee | Corded belt sander (Grainger 2Z963) | 4" x 24" | Yes — grainger.com |
| Milwaukee | 2482-20 M12 FUEL Bandfile | 1/2" x 18" | Yes — Home Depot |
| Milwaukee | 2483-20 M12 FUEL Bandfile | 3/8" x 13" | Yes — milwaukeetool.com |
| Ryobi | BE319 | 3" x 18" | Yes — Home Depot |
| Craftsman | CMEW213 | 3" x 21" | Yes — craftsman.com |
| Skil | 7510-01 | 3" x 18" | Yes — skil.com |
| Black+Decker | DS321 Dragster | 3" x 21" | Yes — blackanddecker.com |
| Bauer (Harbor Freight) | 57587 | 3" x 21" | Yes — harborfreight.com |
| Triton | TA1200BS | 3" x 21" (76 x 533 mm) | Yes — tritontools.com |
| Metabo HPT (Hitachi) | SB8V2 / SB8V2M | 3" x 21" | Yes — metabo-hpt.com |
| Porter-Cable | 352VS | 3" x 21" | No — reseller listings only, no live manufacturer page |
| Porter-Cable | 362 / 363 | 4" x 24" | No — long discontinued, reseller listings only |
Benchtop belt and belt/disc sanders
| Brand | Model | Belt size | Verified |
|---|---|---|---|
| WEN | 6515 / 6515T | 1" x 30" | Yes — Home Depot |
| WEN | 6502T | 4" x 36" | Yes — wenproducts.com |
| Rikon | 50-151, 50-1305 | 1" x 30" | Yes — rikontools.com |
| Rikon | 50-112 | 4" x 36" | Yes — rikontools.com |
| Rikon | 50-120, 50-122 | 6" x 48" | Yes — rikontools.com |
| Jet | J-41002 (577004) | 2" x 42" | Yes — jettools.com |
| Jet | JSG-6DC / JSG-6DCK (708599) | 6" x 48" | Yes — jettools.com |
| Jet | OES-689 edge sander | 6" x 89" | Yes — Home Depot |
| Grizzly | G1183, G1276 | 6" x 48" | Yes — grizzly.com |
| Grizzly | G1015 knife grinder | 2" x 72" | Yes — grizzly.com |
| Grizzly | G0563 oscillating edge sander | 6" x 89" | Yes — Home Depot |
| Grizzly | G0839P edge sander | 6" x 79" | Yes — Home Depot |
| Grizzly | G9985 industrial edge sander | 9" x 138-1/2" | Yes — Home Depot |
| Delta | 31-695 (6" belt / 9" disc) | 6" x 48" | Yes — Delta 31-695 manual (PDF) |
| Powermatic | 31A | 6" x 48" | Yes — Model 31A manual (PDF) |
| Bucktool | BD4603, BD4801-M | 4" x 36" | Yes — bucktool.com |
| Palmgren | 9681061 | 2" x 42" | Yes — palmgren.com |
| Ryobi | BD4601G | 4" x 36" | Yes — Home Depot |
| Bauer (Harbor Freight) | 58339 | 4" x 36" | Yes — harborfreight.com |
| Central Machinery (Harbor Freight) | 58360 | 4" x 36" | Yes — harborfreight.com |
| Kalamazoo Industries | 1SM | 1" x 42" | Yes — kalamazooind.com |
2x72 belt grinders (knife making, tool and die, metal finishing)
Every machine in this class runs the same belt: 2" x 72".
| Brand | Model | Belt size | Verified |
|---|---|---|---|
| Stephen Bader | BIII bench model | 2" x 72" | Yes — stephenbader.com |
| Beaumont Metal Works | KMG | 2" x 72" | Yes — beaumontmetalworks.com |
| Reeder Products | 2x72 grinder | 2" x 72" | Yes — reederproducts.com |
| AmeriBrade | 2x72 packages | 2" x 72" | Yes — ameribrade.com |
| Burr King | 960-272 | 2" x 72" | Yes — burrking.com |
| Grizzly | G1015 | 2" x 72" | Yes — grizzly.com |
| Wuertz Machine Works | TW-90 | 2" x 72" | No — community sources only, no current manufacturer spec page found |
Oscillating spindle, edge belt and file/band-file sanders
| Brand | Model | Belt size | Verified |
|---|---|---|---|
| Ridgid | EB4424 oscillating edge belt/spindle | 4" x 24" | Yes — ridgid.com |
| Milwaukee | 2482-20 | 1/2" x 18" | Yes — Home Depot |
| Milwaukee | 2483-20 | 3/8" x 13" | Yes — milwaukeetool.com |
| Astro Pneumatic | 3037 air belt sander | 1/2" x 18" | Yes — astrotools.com |
| Astro Pneumatic | 3035 air belt sander | 3/4" x 20-1/2" | Yes — astrotools.com |
| Dynabrade | 40320 Dynafile II | 1/4"–3/4" wide x 18" long | Yes — Dynabrade listing |
| Dynabrade | 40352 Dynafile II | 1/8"–3/4" wide x 18" long | Yes — Dynabrade listing |
| Makita | 9031 | 1-1/8" x 21" | Yes — makitatools.com |
Floor sanders
| Brand | Model | Belt size | Verified |
|---|---|---|---|
| Clarke / American Sanders | EZ-8 | 8" x 19" | Yes — Home Depot (Diablo EZ-8 belts) |
| Clarke / Hummel | Drum machines using the long belt | 7-7/8" x 29-1/2" | Size verified; model-by-model mapping not verified |
Wide belt sanders
Wide belt machines are the one category where the machine name will not tell you the belt. A 37" Timesaver-style sander can take a 60", 75" or 103" long belt depending on the head and platen configuration. Measure the belt on the machine, or read the plate. Common sizes in production use are 25x48, 25x60, 25x75, 36x60, 36x75, 37x60, 37x75, 37x103, 43x60, 43x75, 43x85, 52x75, 52x103 and 52x138.
How to measure a belt you already have
Take the belt off the machine and lay it flat so it forms a flattened loop, like an envelope.
Width: measure across the abrasive face, edge to edge. Ignore the joint tape on the back — on some butt-spliced belts the tape is slightly narrower than the cloth.
Length: measure the flat loop from the fold at one end to the fold at the other, then multiply by two. A 3" x 21" belt lays flat at 10-1/2". This is the only reliable tape method.
Why a tape run around the inside gives you a different number
People try to measure belt length by pushing a tape into the inside of the belt and running it around. It almost always reads short — usually by 1/4" to 3/4" on a small belt, and by an inch or more on a long one.
Three reasons. First, a limp belt off the machine will not hold a true circle, so the tape cuts across the corners instead of following the actual loop. Second, abrasive belt length is a nominal dimension measured under a specified tension on a calibrated fixture. Off the machine there is no tension. Third, cloth backing has some stretch in it, and a used belt that has been tensioned for hours is not the same length it was new.
The flat-fold-times-two method sidesteps all of that because you are measuring a doubled straight line, not a curve.
Measuring off the machine itself
If you have no belt at all, set the tensioner to the middle of its travel, run a piece of non-stretch string or a steel tape around the wheel path, mark it, and measure the marked length. Then order the nearest standard size — the tensioner exists to take up the difference.
What to do when your size is discontinued or was never common
Older machines, imports, and shop-built grinders frequently need a size nobody stocks. Common orphans we get asked for: 3" x 23-3/4", 2-1/2" x 60", 6" x 80", 4" x 21-3/4", 1-1/2" x 30", 9" x 48". Your options, in order:
- Check whether a standard size will tension. If your tensioner has an inch of travel, a belt half an inch off will often run fine. Too short and it will not go on; too long and it will not track.
- Have the size made. This is the real answer for an orphan size. We convert and splice sanding belts through our Anaheim operation, in widths from 1/4" to 60" and lengths up to 400", in about three business days with low minimums. Send the size and the material you're working and we'll quote within 24 hours.
- Do not modify a belt. Cutting a wide belt down narrower leaves an unsupported edge that will fray and can throw the belt. It is not worth the risk.
Request a custom sanding belt quote
Belt direction and joint arrows
Look at the back of the belt. If there is an arrow, it means something.
Lap-spliced belts have the two ends overlapped and bonded. They are directional. Run the belt so the workpiece hits the covered edge of the lap first, not the exposed leading edge — that's what the arrow indicates. Run one backwards and the work catches the trailing edge and can peel the joint open. Lap splices stay flexible and handle heat well, which is why they persist in some applications.
Butt-spliced belts have the ends meeting edge to edge over a tape on the back. They are bi-directional: no arrow required, and you can run them either way. That is also a practical trick — when a belt starts to load or glaze, pull it off and put it back on the other way around. You get some cut back for free. Butt splices are the industry standard now because they leave no joint mark on the work.
A belt that thumps, snakes, or walks off the wheel is usually a tracking or tension problem, not a joint problem — but a belt installed backwards on a lap splice will fail fast and loudly.
A note on sizes we carry
Between our catalog and our custom work we cover dozens of widths and lengths, in aluminum oxide (cloth and paper), zirconia, premium ceramic, silicon carbide, AO J-flex, and non-woven surface conditioning, from 24 grit through 800.
Frequently asked questions
How do I know what size sanding belt my sander takes? Read the size printed on the belt currently installed, or check the machine's model description — most handheld and benchtop sanders name the belt size in the product name (a Makita 9403 is a 4x24, a Rikon 50-120 is a 6x48). If neither is available, lay the old belt flat, measure fold to fold, and double it.
What is the most common sanding belt size? For handheld sanders, 3" x 21" is the most common size in the US, followed by 3" x 18" and 4" x 24". For benchtop combo sanders, 4" x 36" and 6" x 48" dominate. For metalworking and knife making, 2" x 72" is the standard.
Can I use a 3x21 belt on a 3x18 sander? No. The width is right but the length is not, and the tensioner cannot take up three inches. Belt length has to match within roughly the travel of your tension arm, which on most handhelds is well under an inch.
Why does my tape measure say my belt is shorter than the size printed on it? Belt length is a nominal dimension measured under tension on a calibrated fixture. A loose belt will not hold a true circle, and a flexible tape pushed inside it cuts the corners. Lay the belt flat, measure from fold to fold, and multiply by two — that will match the printed size.
Does sanding belt direction matter? It matters on lap-spliced belts, which have an arrow on the back showing the running direction. Butt-spliced belts are bi-directional and can be run either way — you can even reverse a partly loaded belt to bring back some cut.
What belt does a 2x72 knife grinder take? 2" x 72", on every common machine — Bader, KMG, Burr King, Reeder, AmeriBrade, TW-90 and the Grizzly G1015. That standardization is the main reason the format won.
My machine's belt size isn't sold anywhere. What now? Have it made. We convert belts in-house from 1/4" to 60" wide and up to 400" long, with low minimums; ask for the current lead time and a contact us for the current quote time. Send us the width, length and what you're sanding.
What grit should I start with? For stock removal and shaping, 36–60. For general smoothing, 80–120. For finish prep, 180–320. For pre-polish and hand-finish prep, 400–800. Do not skip more than one step in the progression — you spend more time chasing the scratches from the previous grit than you saved.