Sandpaper grit numbers measure abrasive particle size: a higher number means finer particles and a smoother scratch pattern. Three standards exist worldwide — CAMI (North America), FEPA (Europe and most of the world), and JIS (Japan). They are nearly interchangeable at coarser grits but diverge noticeably above P220/320.
How it works
Each standard uses a similar approach: particle size is determined by sieving through meshes of known dimensions.
- CAMI (Coated Abrasives Manufacturers Institute): the traditional US standard. Numbers like 80, 120, 220.
- FEPA (Fédération Européenne des Fabricants de Produits Abrasifs): the European/international standard, prefixed with P (P80, P120). Nearly equivalent to CAMI below P220, then diverges — FEPA P320 is finer than CAMI 320.
- JIS (Japanese Industrial Standard): uses # prefix (#80, #120). Very close to FEPA.
Most sandpaper sold globally today uses FEPA P-grades, even in the US.
Practical examples
Example 1 — Wood finishing sequence. Strip old finish with P80 → shape with P120 → smooth with P180 → final sand before staining with P220. Between coats of finish: P320–P400. Final buffing: P600–P1200.
Example 2 — Automotive wet sanding. After applying clear coat, level runs and orange peel with P1000–P1500 wet sanding, then buff out scratches with P2000–P3000 before machine polishing.
Example 3 — Concrete or masonry. P40–P60 for heavy material removal from concrete. P80–P120 for rough leveling. Masonry work rarely requires finer than P150.
Common mistakes
- Using too fine a grit too soon. Skipping grits leaves deep scratches from a coarser pass that a fine grit cannot remove efficiently. Work through the sequence.
- Sanding across the grain in woodworking. Always sand parallel to wood grain (or in circles for orbital sanders) to avoid visible scratches.
- Confusing FEPA P320 with CAMI 320. FEPA P320 is significantly finer than CAMI 320. When comparing sandpaper specifications across brands, check which standard applies.
- Not cleaning between grits. Coarser particles from previous grit trapped under the work piece will continue scratching at the finer grit stage.
International and regional variations
| Standard | Region | Prefix | Coarse end | Fine end |
|---|---|---|---|---|
| CAMI | North America | None (e.g. "80 grit") | 24 | 2000+ |
| FEPA | Europe / global | P (e.g. "P80") | P12 | P5000 |
| JIS | Japan | # (e.g. "#80") | #12 | #8000 |
| FEPA Macro (F-grade) | Europe (loose abrasives) | F (e.g. "F80") | F4 | F1200 |
Quick reference — grit by use
| Grit range (FEPA) | Use |
|---|---|
| P40–P60 | Heavy stock removal, stripping old finish, shaping |
| P80–P100 | Rough sanding, floor sanding, removing mill marks |
| P120–P150 | General sanding, smoothing after P80 |
| P180–P220 | Pre-finish sanding, light scratch removal |
| P320–P400 | Sanding between coats, light paint prep |
| P600–P1000 | Wet sanding, fine polishing |
| P1200–P3000 | High-gloss automotive finishing, mirror polish |