Looking for the right cartridge to buy to fit your fountain pen? Well, you’ve come to the right place! I’ve compiled the biggest list of brand-cartridge compatibility I can for you.
International fountain pen cartridges come in two standard sizes: 38mm short and 73mm long; both have the same size opening to fit around the tube shown in the drawing to the right. 73mm are more convenient because they hold more ink, but if you have a short pen or there are any obstructions inside of barrel it may not fit the longer cartridge.
My Kaweco Dia2, for instance, can fit two 38mm cartridges back-to-back (A.K.A. piggybacking) inside of the barrel ensuring you never run out of ink as it has a longer barrel. I could also use a 73mm cartridge in it.
The main difference between universal and proprietary cartridges are the different diameter openings that wrap around the tube.
If your pen is on the proprietary list below, it will only fit its own brand of cartridges. Here are the charts:
Fountain Pens That Use International Cartridges:
Bossert & Erhard
Caran d’ Ache
Jean Pierre Lepine
Museum of Modern Art
Sheaffer (VFM only)
You *can* get international short cartridges in beautiful colors! Here are some:
Proprietary Cartridges, Not Compatible with Universal/International:
I own a few of these fountain pen brands, and I’m a huge proponent of syringe-refilling their cartridges. I haven’t had to buy new ones yet, get to refill them with whatever beautiful bottled ink I love and I’m saving the environment.
HUGE thanks to these sites, whose articles I used to cross-check all of these brands to ensure I am providing accurate information to you:
If you’d like to move up into bottle feeding your baby, check out my article on the best bottled fountain pen inks.