Fountain Pen Nib Widths
Pens, Inks & Leads · 8 specs
Direct Answer
Fountain Pen Nib Widths are standardized tip grinding grades that determine ink line width, categorized from Extra Fine (EF) to Double Broad (BB) and Calligraphic Stubs (1.1 mm to 1.5 mm). Crucially, Japanese nibs (Pilot, Sailor, Platinum) write approximately one full step finer than Western nibs (Pelikan, Lamy, Kaweco) due to the dense stroke requirements of East Asian kanji characters.
Source: Nib Manufacturers Association / Pilot Corporation / Pelikan GmbH Technical Guides · Last reviewed Aug 28, 2026
Specs
| Extra Fine (EF)–Japanese | Approx. 0.20 to 0.28 mm line width (hairline precision) |
| Extra Fine (EF)–Western | Approx. 0.35 to 0.40 mm line width (similar to Japanese Fine) |
| Fine (F)–Japanese | Approx. 0.30 to 0.38 mm line width (standard everyday Japanese notebook writing) |
| Fine (F)–Western | Approx. 0.50 to 0.60 mm line width (similar to Japanese Medium) |
| Medium (M)–Japanese | Approx. 0.50 to 0.58 mm line width |
| Medium (M)–Western | Approx. 0.70 to 0.80 mm line width (plentiful wet ink flow) |
| Broad (B) & Stub (1.1 / 1.5 mm) | Broad: 0.9–1.0 mm | Stub: Flat rectangular tip with thick downstrokes and hairline cross-strokes |
| Tipping Material | Sintered osmium/iridium/ruthenium platinum-group alloy sphere welded to gold or steel tines |
The Cultural Origin of Japanese vs Western Sizing
Writing complex multi-stroke Japanese kanji and Chinese Hanzi characters within standard 7 mm notebook rules requires hairline stroke separation without ink blobbing, forcing Japanese nibmeisters (Pilot, Sailor, Platinum) to grind their EF and F nibs down to 0.25 mm. Western cursive writing emphasizes smooth continuous gliding with wet shading, resulting in wider Western nib grinds (Pelikan, Lamy).