Grit Size Conversion Chart
Reference chart for converting between different grit size standards (FEPA, ANSI, JIS, Micron, Mesh)
Grit Size Conversion Chart
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Important — these standards are NOT a 1:1 conversion
FEPA-P (FEPA-43-GB), ANSI/CAMI B74.18, and JIS R6010 use essentially the same grit numbers at coarse sizes (about 220 and coarser) but diverge increasingly at finer sizes — by the fine end, US/CAMI 600 grit ≈ FEPA P1200, and US 1200 ≈ P2500. The micron column below shows the FEPA-P particle size for the row's P-grade. The ANSI and JIS numbers in the same row are the closest grit-number neighbors, not the equivalent particle size in those standards. For ANSI/CAMI and JIS particle sizes at the fine end, use the divergence table below.
For most metallographic prep work, identify which scale your paper is sold under and stay in that scale — don't substitute "P1200" for "1200 grit" if your supplier ships ANSI/CAMI papers.
| FEPA-P | ANSI (nearest no.) | JIS (nearest no.) | FEPA-P size (μm) | Mesh | Category |
|---|---|---|---|---|---|
| P12 | 12 | 12 | 1815 | 12 | Very Coarse |
| P16 | 16 | 16 | 1324 | 16 | Very Coarse |
| P20 | 20 | 20 | 1000 | 20 | Very Coarse |
| P24 | 24 | 24 | 764 | 24 | Coarse |
| P30 | 30 | 30 | 642 | 30 | Coarse |
| P36 | 36 | 36 | 538 | 36 | Coarse |
| P40 | 40 | 40 | 425 | 40 | Coarse |
| P50 | 50 | 50 | 336 | 50 | Medium |
| P60 | 60 | 60 | 269 | 60 | Medium |
| P80 | 80 | 80 | 201 | 80 | Medium |
| P100 | 100 | 100 | 162 | 100 | Medium |
| P120 | 120 | 120 | 125 | 120 | Fine |
| P150 | 150 | 150 | 100 | 150 | Fine |
| P180 | 180 | 180 | 82 | 180 | Fine |
| P220 | 220 | 220 | 68 | 220 | Fine |
| P240 | 220 | 240 | 58.5 | — | Very Fine |
| P280 | 240 | 280 | 52.2 | — | Very Fine |
| P320 | 280 | 280 | 46.2 | — | Very Fine |
| P360 | 320 | 320 | 40.5 | — | Very Fine |
| P400 | 320 | 360 | 35.0 | — | Very Fine |
| P500 | 360 | 400 | 30.2 | — | Ultra Fine |
| P600 | 400 | 500 | 25.8 | — | Ultra Fine |
| P800 | 400 | 600 | 21.8 | — | Ultra Fine |
| P1000 | 500 | 700 | 18.3 | — | Ultra Fine |
| P1200 | 600 | 800 | 15.3 | — | Ultra Fine |
| P1500 | 800 | 1000 | 12.6 | — | Ultra Fine |
| P2000 | 1000 | 1200 | 10.3 | — | Ultra Fine |
| P2500 | 1200 | 1500 | 8.4 | — | Ultra Fine |
Where FEPA-P, ANSI/CAMI, and JIS diverge
Beyond roughly 240 grit, the same grit number means very different particle sizes in each standard. If your paper is labeled "1200 grit" with no other context, the actual abrasive size depends entirely on which standard the manufacturer used. Use this table to translate between them.
| Grit number | FEPA-P (μm) | ANSI/CAMI (μm) | JIS R6010 (μm) |
|---|---|---|---|
| 120 | 125 | ~125 | ~125 |
| 240 | 58 | 52 | 57 |
| 320 | 46 | 35 | 40 |
| 400 | 35 | 22 | 32 |
| 600 | 26 | 15 | 20 |
| 800 | 22 | 12 | 14 |
| 1200 | 15 | 8 | 9.2 |
| 1500 | 13 | 6 | 8 |
| 2000 | 10 | 5 | 6.7 |
| 2500 | 8.4 | — | — |
Source: FEPA 43-GB, ANSI B74.18, JIS R6010. Values rounded to typical manufacturer ranges. The grinding ladder used in our guides (P120 → P320 → P600 → P800 → P1200 in FEPA-P) corresponds roughly to US/CAMI 120 → 280 → 360 → 400 → 600 in actual particle size.
Notes
- • FEPA-P: Federation of European Producers of Abrasives, P-grade (FEPA 43-GB). Most European and many international metallographic papers.
- • ANSI/CAMI: ANSI B74.18, the standard used by most North American manufacturers (also called CAMI for Coated Abrasive Manufacturers Institute).
- • JIS: JIS R6010 — Japanese Industrial Standard.
- • Mesh: US Standard mesh size (screen openings per linear inch in the screen used to grade the abrasive). Only macrogrits (~220 and coarser) are screen-graded; finer grades are classified by sedimentation, so no mesh equivalent is listed.
- • Particle-size figures are nominal; manufacturer-specific values can vary by ±10–20%.
- • For acceptance work, verify abrasive standard and particle size on the manufacturer's data sheet.