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40grit sandpaper

Extra Coarse

Heavy stock removal, paint stripping, rough lumber.

40 grit in other scales

If the pack says 40 (CAMI, most US paper)

~425 µmAbout the same as P40.

If it says P40 (FEPA, Festool, Mirka, Norton 3X)

~425 µmAbout the same as CAMI 40.P40, converted →

Sizes are average particle diameters from the published CAMI and FEPA tables. Full ladder in the grit chart; any grade on any scale in the grit converter.

What 40 grit is for

40-grit is the heaviest production sandpaper in common use. It removes paint, weathered wood, mill scale, and old finishes faster than anything finer. Expect deep, visible scratches: 40-grit is for stripping, not shaping.

Projects at 40 grit

  • · Stripping old paint from exterior siding
  • · Removing weathered surface from reclaimed lumber
  • · Floor refinishing (first pass on hardwood floors)
  • · Knocking down dried glue or epoxy
  • · Rough leveling on edge-glued panels

Abrasive materials

  • · aluminum oxide
  • · zirconia (for belts and discs)
  • · ceramic (3M Cubitron, Norton Blue Fire)

Common mistake

Don’t finish on 40. The scratches it leaves are visible through stain and most paint. Always step up through 60–80–120 before finish.

60 grit (the step after) →

Top pick at 40

Norton 3X Sheet Sandpaper, 80 Grit (20-pack)

When 100-grit has been disappointing you and you're done being patient.

Check priceReview

Catalog fit

58

Current SKU matches in this grit lane.

Common forms

5

Forms represented here, led by discs.

Head to head

4

Comparison pages currently touching this stage of the sanding climb.

Use this grit when

The surface still needs this stage.

  • · Heavy stock removal, paint stripping, rough lumber.
  • · This is a cutting stage, not a finish stage. Use it to remove material, not to fake smoothness.
  • · On this site, 40 grit shows up most around heavy stock removal, 3×21 belt sanders, contour sanding, and paint stripping.

Skip this grit when

The job is earlier or later than this.

  • · Skip this grit for between-coat work, final finish prep, or anything already close to smooth.
  • · Skip the urge to jump straight here from a very coarse grit; the scratch pattern underneath will usually survive the shortcut.

Recommended at this grit.

Head to head

Comparisons in this lane.

3M 9×11 40-Grit Sandpaper (5-pack) vs. Norton 3X Sheet Sandpaper, 80 Grit (20-pack)

How rough is the surface, and how much do you want left of it.

Read the breakdown →

3M Pro Grade Precision Assorted Pack vs. Gator Finishing Multi-Grit 9x11 Sandpaper Pack

Both cover the range. One holds up longer.

Read the breakdown →

POWERTEC 3" × 21" Sanding Belt Pack (20-pack) vs. 4" × 36" Zirconia Sanding Belt Variety Pack (10 belts, 5 grits)

Which belt sander is on your bench.

Read the breakdown →

3M Pro Grade 2.75" × 25yd Sanding Roll, 80 Grit vs. 3M Stikit 426U Silicon Carbide Roll, 120 Grit

Same form factor. Different surface, different grain.

Read the breakdown →

Questions people ask

The practical part.

What is 40 grit actually for?

40 grit is for heavy stock removal, paint stripping, rough lumber. This is a cutting stage, not a finish stage. Use it to remove material, not to fake smoothness.

What should come before and after 40 grit?

40 is the opening move. Step up into 60 or a nearby grit before you ask the surface to look finished.

Which forms make the most sense at 40 grit?

On UltraRough, this grit shows up most in discs, belts, and sheets. That reflects where shoppers usually need this cut level in the real world.

Keep moving

Follow the climb.

60 gritThe next step after 40 grit.DiscsSee discs that commonly show up in this lane.BeltsSee belts that commonly show up in this lane.SheetsSee sheets that commonly show up in this lane.Use the grit selectorStart from the project instead of the number.Read the full grit chartSee the entire progression from coarse to mirror.Sandpaper grit chart: coarse to fineThe full range mapped to projects — every grit from 40 to 3000.Find the right grit for your projectTell us the job; we'll tell you where to start and where to stop.
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