So how big are my pens? Here’s a guide.

So how big are these pens?

When I list diameter of a pen, it’s at the barrel threads, where the cap screws on.
So here’s a list of my basic pen sizes with the approximate maximum section diameter as well.

Slim – .45″/11mm thick with 10mm thick section.
Small – .50″/13mm thick with 12mm thick section.
Medium – .55″/14mm thick with 13mm thick section.
Oversize – .65″/16mm thick with 15mm thick section.

Real quick – what does that look like?

A US penny is 19mm in diameter – about the same as the caps on my oversize pens.
A US dime is about 18mm in diameter.

An old Esterbrook Jay is 11.4mm at the threads.
Montblanc 146 is 12.2mm at the threads – compare to my Small.
Montblanc 149 is 14.3mm at the threads – compare to my Medium.
1935 Parker Duofold Sr. Big Red is 12.5 at the threads – compare to my Small.
Parker 51 about 12mm at the ring.
Pelikan 200/400/600 all about 11mm at the threads – compare to my Slim.
Pelikan M800 is 12.5mm at the threads.
Pelikan M1000 is about 13.5mm at the threads – compare to my Medium.
1930 Sheaffer OS Balance 12.5mm at threads.
Sheaffer PFM/Legacy about 12.5mm at section/barrel join.

I hope that helps give some better ideas about my pens.