Fountain Pen Nib Guide: Understanding Sizes, Materials, and Grinds

The nib is the soul of a fountain pen. Everything about the writing experience—the line width, the smoothness, the ink flow, the character of your writing—comes from a small piece of metal at the pen’s tip. Understanding nibs transforms you from someone who uses fountain pens into someone who can choose the right pen for the right task.

Here’s what you need to know.

Nib Sizes: What the Letters Mean

Fountain pen nibs are labeled by line width, but sizing isn’t standardized across manufacturers. A “medium” from one brand can be noticeably different from another’s.

Standard Sizes

Extra-Fine (EF/XF): The finest standard option. Produces a thin, precise line comparable to a 0.3-0.4mm gel pen. Best for small handwriting, detailed work, and cheaper paper (thin lines bleed less). Can feel scratchy—less tipping material means more metal-to-paper contact.

Fine (F): A versatile everyday size. Comparable to a 0.5mm gel pen from Western brands, slightly finer from Japanese brands. Smooth enough for comfortable writing, fine enough for most paper. The safe default choice.

Medium (M): The most popular size. Comparable to a 0.6-0.7mm gel pen (Western) or a fine gel pen (Japanese). Smooth, expressive, shows off ink color and shading. Requires decent paper for best results.

Broad (B): Wide, wet, and dramatic. Produces a line comparable to a thick marker. Beautiful for signatures, display writing, and ink appreciation. Requires fountain-pen-friendly paper—broad nibs on cheap paper produce a feathery mess.

Specialty Sizes

Extra-Broad (BB): Even wider. Rare in everyday pens but available from some manufacturers. Strictly for good paper and visual effect.

Stub/Italic: A flat-ground nib that produces thick horizontal strokes and thin vertical strokes. The variation comes from the nib’s shape, not from pressure. Stubs have slightly rounded edges for smooth writing; italics have sharper edges for crisper thick-thin contrast. Both add calligraphic character to everyday handwriting.

Flex: A nib designed to spread under pressure, producing line width variation based on how hard you press. True vintage flex nibs produce dramatic variation; modern “flex” nibs are usually semi-flex with moderate variation. Flex nibs are for calligraphy and decorative writing, not daily use.

Zoom/Music: Specialty nibs from Japanese manufacturers. The zoom nib varies width based on writing angle. Music nibs have multiple tines for broad, wet lines designed for writing musical scores.

Japanese vs. Western Sizing

This is the most important sizing fact for new fountain pen users: Japanese nib sizes run one full size finer than Western sizes.

A Pilot medium is roughly equivalent to a Lamy or TWSBI fine. A Pilot fine is roughly equivalent to a Lamy or TWSBI extra-fine.

This matters when buying your first pen. If you want a medium-width line, choose Medium from Pilot/Sailor/Platinum or choose Fine from Lamy/TWSBI/Pelikan. Getting this wrong is the most common source of “my new pen writes too thick/too thin” complaints.

For recommendations that account for these sizing differences, see [INTERNAL: choosing-your-first-fountain-pen].

Nib Materials

Steel Nibs

Most fountain pens under $100 have steel nibs. Modern steel nibs are excellent—smooth, durable, and consistent. They’re rigid, meaning line width doesn’t change with pressure (which is actually a feature for everyday writing: consistent lines without effort).

Good steel nibs to know: Pilot’s steel nibs (found on the Metropolitan, Kakuno, and Prera) are among the smoothest. JoWo nibs (found on TWSBI, many independent pen makers) are reliable and consistent. Lamy nibs are good with occasional quality control variability.

Gold Nibs

Gold nibs (typically 14K or 18K) are found on pens above $100-150. Gold is softer than steel, which affects the writing experience:

• More spring: Gold nibs have a subtle bounce that steel nibs don’t. This cushioned feel is often described as “buttery” and is the primary luxury of gold nibs.
• Not inherently smoother: A well-tuned steel nib can be as smooth as a gold nib. Smoothness comes from the tipping material, not the nib body.
• Not more durable: Steel is harder than gold. Steel nibs arguably last longer.

Gold nibs are a luxury, not a necessity. If you enjoy fountain pens and can afford the upgrade, the writing feel is noticeably different and widely preferred. If budget is a concern, excellent steel nibs will serve you for a lifetime.

Titanium and Other Materials

Titanium nibs offer some of gold’s springiness at a lower price point. They’re less common but available from some manufacturers. Palladium nibs and other exotic materials exist in the high-end market.

Nib Grinds

The “grind” refers to how the tipping material (the small ball of hard alloy at the nib’s tip) is shaped. Standard nibs come with a round tip, but nibmeisters (specialized craftspeople) can custom-grind nibs for different writing characteristics:

Round: Standard. Writes the same width in all directions. Most pens come with round-ground nibs.

Italic: Ground flat for thick-thin variation. Produces wider horizontal strokes and thinner vertical strokes. Beautiful but less smooth than round grinds.

Stub: A rounded italic. Same thick-thin variation but smoother because the edges are rounded. More forgiving of writing angle.

Cursive Italic (CI): A compromise between italic and stub. Moderate edge sharpness for good thick-thin contrast with reasonable smoothness.

Architect: The reverse of italic—thin horizontal strokes and thick vertical strokes. Unusual and distinctive. Created by grinding the nib rotated 90 degrees from standard italic.

Needlepoint: An extremely fine round grind. Produces a very thin line. The finest option available. Can feel scratchy if not expertly done.

Custom grinds are typically performed by nibmeisters who you can find at pen shows or through online services. Prices range from $25-75 depending on the grind. It’s an advanced fountain pen pursuit, but it lets you create exactly the writing experience you want.

Nib Maintenance

Proper nib care keeps your pen writing well:

Cleaning: Flush the nib and feed with water when changing inks. For stubborn ink residue, a dilute solution of pen flush or a drop of dish soap in water helps. Never use alcohol or harsh solvents.

Storage: If you won’t use a pen for more than a few weeks, flush it clean and store it empty. Ink left in a pen for months can dry and clog the feed.

Alignment: If your nib starts writing scratchy, check the tines under magnification (a loupe or phone camera with macro mode). The tines should be aligned—if one is higher than the other, the nib will scratch. Gentle adjustment with clean fingers can fix minor misalignment.

Smoothing: A slightly scratchy nib can often be improved by writing figure-eights on a brown paper grocery bag. The micro-abrasive surface smooths rough tipping material. For more serious issues, a nibmeister is the safe option.

For complete pen care procedures, see [INTERNAL: pen-maintenance-basics].

Choosing Your Nib

For your first fountain pen, choose a medium (Western) or fine (Japanese) nib. This gives you a line width that’s expressive enough to show ink color and smooth enough for comfortable daily writing.

Once you’re comfortable, experiment. Try a stub for your journal. Try a fine for your work notebook. Try a broad for letter writing. The joy of fountain pens is that different nibs create different writing experiences—and finding the combination that fits your hand, your paper, and your writing is a deeply satisfying pursuit.