Short answer
Buy a medium bullet (1.8 to 2.5 mm) first: it fills small shapes and writes legibly. Add an extra fine 0.7 mm for outlines and dots, and a broad 8 to 15 mm only if you cover big areas like canvas backgrounds or pumpkins.
Filter by tip shape
Scale
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0.7 mmExtra fine pinpin
Outlines, tiny lettering, dot work, fixing edges
Examples: Posca PC-1MR, Montana 0.7 mm, Artistro extra fine
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0.9 to 1.3 mmFine bulletbullet
Line work, writing on rocks, small details
Examples: Posca PC-3M
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1 to 2 mmFine roundbullet
Detail with a sturdier nib
Examples: Molotow ONE4ALL 1 to 2 mm
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1.8 to 2.5 mmMedium bulletbullet
The all-rounder: fills, lettering, rock designs, pumpkins
Examples: Posca PC-5M, Liquitex fine 2 mm, Montana 2 mm, Molotow 2 mm
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3 mmMediumbullet
Filling small shapes, bold lettering
Examples: Artistro medium
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4 mmMedium broadbullet
Faster fills, thick outlines
Examples: Molotow ONE4ALL 4 mm
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4.5 to 5.5 mmBroad bulletbullet
Background areas on small pieces, signs
Examples: Posca PC-7M
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8 mmBroad chiselchisel
Base coats, curves, block lettering
Examples: Posca PC-8K, Molotow ONE4ALL 8 mm
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15 mmExtra broadchisel
Backgrounds, canvas blocks, murals
Examples: Posca PC-17K, Liquitex wide, Montana 15 mm, Molotow 15 mm, Artistro jumbo
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1 to 4 mmSemi-flexible brushbrush
Lettering with thick and thin strokes, petals
Examples: Posca PC-5BR
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1 to 10 mmSoft brushbrush
Calligraphy, washes of color, organic shapes
Examples: Posca PCF-350
Actual size uses CSS millimeters, so it is close on most screens but not exact. Brush and range tips are drawn at a typical width. Sizes come from maker pages.
Tip shapes explained
| Shape | What it does | Watch out for |
|---|---|---|
| Pin (extra fine) | Hard plastic or metal-sleeved tip for the thinnest, most consistent lines. | Can scratch on rough rock; splatters if over-pumped. |
| Bullet | Rounded fiber tip. The all-rounder for writing, outlines and small fills. | Wears to a wider line on rough surfaces over time. |
| Chisel | Flat wedge. Broad strokes on its side, thinner lines on its edge. | Leaves streaks on big areas if you go over wet paint. |
| Brush | Flexible nib that swells with pressure for thick and thin strokes. | Needs a light hand; some brush sets are watery. |
| Dual tip | Two tips on one barrel, often brush plus fine. | Usually cotton core: mess-free but less opaque. |
How tip size changes coverage
A 15 mm tip lays down roughly ten times the width of a 1.5 mm tip in one pass, so a background that takes minutes with a broad marker takes far longer with a fine one, and the many overlapping fine strokes show as texture. Use the broad tip for the base, then switch to medium and fine for detail on top once the base is dry.
For outlines on dark surfaces, a fine tip in white or a light color needs more than one pass. Independent testing found white pens vary a lot between brands; the Artistro and Arteza extra fine whites were among the strongest.
Which sizes to buy for each job
- Rock painting: fine 0.7 to 1.3 mm plus medium 1.8 to 2.5 mm. Rock painting guide.
- Canvas: broad 8 to 15 mm for blocks, medium for edges. Canvas guide.
- Journals and paper: extra fine and fine. Fine tip guide.
- Lettering: a brush tip. Brush tip guide.
- Pumpkins: broad chisel for base color, medium for patterns. Pumpkin guide.
Questions people ask
What is the difference between 0.7 mm and 1 mm tips?
Both draw fine lines. A 0.7 mm pin tip is stiffer and more precise for outlines and lettering; a 1 mm round tip covers a little faster and tends to be more forgiving on rough surfaces like rock.
Is the tip size the same as the line width?
Roughly. Pressure, surface texture and how wet the tip is all change the line. Bullet tips are quoted as a range for that reason, for example Posca lists its PC-5M at 1.8 to 2.5 mm.
Can I change the tip?
On many pump-action markers, yes. Posca says the PC-5M tip is easily reversible, Liquitex sells replacement nib packs, and Molotow and Montana sell spare parts. Direct-ink and cotton core markers usually cannot be changed.
Sources
Last reviewed 2026-10-12. Specs and availability change; check the listing before you buy.