Grit Size Converter
Convert between ANSI/CAMI, FEPA (P-grade), JIS, and micron-based grit sizing standards used in metallographic sample preparation. ANSI/CAMI is the standard PACE Technologies leads with for North American customers. Results update as you type.
About the Standards
Different standards use different numbering systems for abrasive grit sizes. This converter helps you find approximate equivalents across standards.
- ANSI / CAMI: The standard PACE Technologies uses for North American sample-prep consumables (ANSI B74.12 / B74.10). Macrogrits (≤220) share designation numbers with FEPA P. Above 220, ANSI uses a separate numbering scale.
- FEPA (P-Grade): ISO 6344 standard for coated abrasives, common in Europe and on imported papers. Micron values represent median particle size (d50). Covered here: P12 through P5000.
- JIS: Japanese Industrial Standard R6001. Macrogrits use the same sieve-based numbering as ANSI/FEPA. Microgrits (above #220) diverge in numbering and are matched here by closest particle size.
- Micron (μm): Particle size in micrometers. Entering a micron value snaps to the closest known grit. Diamond and colloidal silica abrasives are graded by micron only; they have no grit number.
Note: Cross-standard equivalents above ANSI 220 / P220 are approximate and matched by closest particle size, not by grit number. These standards define particle size differently (sieve analysis vs. sedimentation vs. laser diffraction), so exact equivalence is not possible. Always verify critical specifications with your abrasive supplier.
Final-polish abrasives (diamond, colloidal silica, alumina) are graded by micron only; they have no ANSI / FEPA / JIS grit number. When you enter a micron value in the final-polishing range, the result will surface the matching diamond / CS / alumina sizes.
Grit Sizes by Preparation Stage
Sample preparation typically follows a sequence from coarse to fine, with each step removing the damage left by the previous one. Use this as a rough guide; the optimal sequence depends on the material, its hardness, and the prep equipment you have available.
Aggressive material removal to flatten the sample and erase cutting damage. SiC paper or coarse-bonded diamond discs. The fastest step but introduces the deepest subsurface damage.
Progressive refinement of the ground surface. Each step removes the scratches from the previous; rotating the sample 90° between steps makes the transition visible under the microscope.
Diamond suspension or paste on a cloth pad removes the remaining fine-grinding scratches and begins to produce a reflective surface. Sometimes called "diamond polishing."
Final mirror finish using fine diamond, colloidal silica, or alumina. Removes residual deformation so the sample is ready for etching, microscopy, and EBSD.
Common Abrasive Types
The same grit number can mean a different abrasive depending on the product. Knowing which abrasive you are working with matters as much as the grit size itself.
Silicon Carbide (SiC)
The workhorse for grinding most metals. Available as coated papers from ANSI 60 through 1200 (FEPA P60 – P4000). SiC is friable: it fractures during use and keeps cutting edges sharp. Best for general-purpose grinding.
Aluminum Oxide (Al₂O₃)
Tougher and longer-lasting than SiC, used where higher impact strength is required. Common in coated belts, grinding wheels, and as a final-polish abrasive in 1.0, 0.3, and 0.05 μm sizes.
Diamond
The hardest abrasive available. Used as bonded discs for fast fine grinding (45–9 μm) and as suspensions or pastes for polishing (9–0.05 μm). Essential for hard materials, ceramics, and carbides.
Colloidal Silica
Chemo-mechanical polish at 0.02–0.05 μm. Produces strain-free surfaces ideal for EBSD, ion etching, and high-magnification microscopy of soft alloys and difficult materials.
Full Conversion Reference Table
Complete cross-standard table used by this converter. Click any row to load it into the converter above. Macrogrits (ANSI/P 12 – 220) share grit numbers across standards; microgrit equivalents are matched by closest particle size.
| ANSI / CAMI | FEPA (P-Grade) | JIS | Micron (μm) | Stage |
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