Grit Size Converter
Convert between US (ANSI/CAMI) and European (FEPA P-grade) grit size standards for SiC grinding papers, with approximate particle sizes in microns. The two scales are not aliases — they diverge sharply at the fine end.
About Grit Sizes
Different standards use different numbering systems for abrasive grit sizes. This converter helps you find equivalent sizes across standards.
- US (ANSI/CAMI B74.18): The grading printed on most North American grinding papers
- FEPA (P-Grade): European / international standard, marked with a "P" prefix
- Micron: Approximate median abrasive particle size in micrometers
Important: US and FEPA numbers are roughly equal at the coarse end but diverge sharply at the fine end — US 320 ≈ P400, US 400 ≈ P800, and US 600 ≈ P1200. Matching the printed numbers ("400 grit = P400") can put a preparation ladder a full grade off. Conversions are approximate, and vendors vary at the margin; this table covers the grades commonly used for metallographic SiC papers (US 60–2000 / P60–P4000).
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