Most fountain pens use one of three cartridge systems

Replacing an ink cartridge in a fountain pen depends on which type of pen you own. The three main systems are slip-in cartridges (the most common), screw-in cartridges, and squeeze cartridges. Slip-in cartridges slide straight into the barrel and click or snap into place. Screw-in cartridges thread onto the nib section like a bottle cap. Squeeze cartridges are plastic tubes you compress to push ink into an internal reservoir. Your pen's manual or the manufacturer's website will tell you which type yours uses, but you can also identify it by looking at the barrel opening — slip-in cartridges are obvious because they sit visibly in the barrel, while screw-in types have a threaded collar you can see at the nib.

Before you buy replacement cartridges, check the pen's brand and model number. Cartridges are not universal — a Lamy cartridge will not fit a Kaweco, and a Parker will not fit a Pilot. The wrong cartridge either will not insert or will leak. Most pen manufacturers sell cartridges directly, and they are also stocked at office supply stores, art supply shops, and online retailers. A single cartridge costs between $1 and $4 depending on the brand.

Key Takeaways

  • Identify your pen's cartridge type by checking the manual or looking at the barrel opening where the nib attaches.
  • Slip-in cartridges slide straight in and click into place; screw-in cartridges thread onto the nib section; squeeze cartridges compress to fill an internal reservoir.
  • Buy cartridges that match your pen's exact brand and model, because cartridges are not interchangeable between manufacturers.
  • Remove the old cartridge by pulling it straight out (slip-in), unscrewing it (screw-in), or squeezing it empty and removing it (squeeze).
  • Insert the new cartridge firmly until you hear or feel it click or seat, then test the pen on scrap paper before writing on anything important.

How to remove a slip-in cartridge

Slip-in cartridges are the easiest to replace. Unscrew the barrel of the pen — most fountain pens have a barrel that twists apart at the middle, separating the nib section from the back half. If your pen does not unscrew, look for a small button or lever on the barrel; some pens have a push-button release instead. Once the barrel is open, you will see the cartridge sitting inside. Grasp it firmly and pull straight out. Do not twist or rock it side to side, because the nib section is delicate and twisting can damage the feed (the part that controls ink flow).

If the cartridge is stuck, wet a paper towel with warm water and wrap it around the barrel for a few seconds to soften any dried ink seal. Then pull again. If it still will not budge, try wrapping a rubber band around the cartridge for grip, but do not use pliers or anything that could crush the plastic. Once the old cartridge is out, wipe the inside of the barrel with a dry cloth to remove any ink residue.

How to remove a screw-in cartridge

Screw-in cartridges are threaded onto the nib section. Hold the nib section steady with one hand and turn the cartridge counterclockwise (left) with the other. Most screw-in cartridges unthread easily by hand, but if it is tight, wrap a small cloth around it for grip and try again. Do not use a wrench or pliers, which can crack the plastic. Once it is loose enough, unscrew it the rest of the way by hand and set it aside.

Before you install the new cartridge, wipe the threads on the nib section with a dry cloth to remove any dried ink or debris. This prevents the new cartridge from sealing poorly or getting stuck. Then screw the new cartridge on by turning it clockwise (right) until it is snug. You should feel slight resistance, but do not force it — if it will not turn, you may have the wrong cartridge type or the threads may be damaged.

How to remove and install a squeeze cartridge

Squeeze cartridges work differently because they do not click or screw in place. Instead, they sit inside the barrel and you compress them to push ink into a reservoir. To replace one, first unscrew the barrel to access the cartridge. The cartridge will look like a small plastic tube. Squeeze it several times to empty any remaining ink into the reservoir, then pull it straight out. Wipe the inside of the barrel with a dry cloth.

To install a new squeeze cartridge, insert it into the barrel and push it all the way in until it seats firmly. Then squeeze it once or twice to prime the system and push ink into the nib. Test the pen on scrap paper — it may take a few squeezes before ink flows smoothly. If no ink comes out after five or six squeezes, the cartridge may not be seated properly; remove it and try again, making sure it is pushed all the way in.

Testing the pen after cartridge replacement

After you install a new cartridge, always test the pen on scrap paper before using it for writing. Scribble a few lines and circles to make sure ink flows evenly and the nib is not scratchy. If the pen writes smoothly, you are done. If the nib feels dry or scratchy, the cartridge may not be seated properly — remove it and reinstall it, making sure it clicks or seats firmly.

If the pen still does not write after reinstalling, the cartridge may be defective or the wrong type. Check the cartridge box to confirm it matches your pen's brand and model. If it does match and the pen still will not write, try a different cartridge from the same box. If a second cartridge also fails, contact the pen manufacturer or the retailer where you bought the cartridges — they can confirm whether the cartridge is compatible or send you a replacement.

Storing cartridges and preventing leaks

Store unused cartridges in a cool, dry place away from direct sunlight. Heat and light can dry out the ink or damage the plastic. Keep them in their original packaging or in a sealed container so they do not dry out. Most cartridges stay usable for several years if stored properly.

To prevent leaks when carrying a fountain pen, always keep it nib-up in a pen case or pocket. Storing it nib-down allows ink to flow out of the feed and into the cap, which can cause leaks. If your pen does leak, remove the cartridge when ready, wipe the barrel and nib section with a damp cloth, and let them dry completely before installing a new cartridge. Leaking is usually a sign that the cartridge was not seated properly or that the pen was stored nib-down.

When to refill instead of replace

If you use your fountain pen frequently, refilling cartridges with a syringe or converter may be cheaper than buying new cartridges. A converter is a reusable device that screws onto the nib section like a cartridge but has a plunger inside that draws ink from a bottle. Converters cost $5 to $15 and work with any bottled fountain pen ink. A syringe refill involves using a syringe to inject ink directly into an empty cartridge, which costs almost nothing but takes more care to avoid spilling.

Converters are the easier option if you want to switch inks frequently or save money over time. Syringe refills work if you have found an ink you love and want to stick with it. Both methods require the same nib section as cartridges, so you can switch between cartridges and converters or refilled cartridges without any changes to the pen itself.

Frequently Asked Questions

Can I use a cartridge from a different brand in my fountain pen?

No. Cartridges are designed to fit specific nib sections and are not interchangeable between brands. Using the wrong cartridge will either not fit or will leak. Always buy cartridges that match your pen's exact brand and model number.

What should I do if ink leaks after I install a new cartridge?

Remove the cartridge and reinstall it, making sure it clicks or seats firmly into place. Leaks usually mean the cartridge was not inserted all the way. If it still leaks after reinstalling, the cartridge may be defective — try a different one from the same box. Also check that you are storing the pen nib-up, not nib-down.

How long does a cartridge last?

It depends on how much you write. A typical cartridge lasts anywhere from a few days to a few weeks of regular use. Heavy daily writers may go through one cartridge per week, while occasional users might use one cartridge per month. You will know it is time to replace when the ink stops flowing or becomes very faint.

Is it cheaper to refill cartridges or buy new ones?

Refilling with a converter and bottled ink is cheaper over time if you write regularly. A converter costs $5 to $15 once, and bottled ink costs $5 to $10 per bottle and lasts much longer than cartridges. If you write occasionally, buying cartridges is simpler and you will not notice the cost difference.

Can I clean and reuse an old cartridge?

You can rinse an old cartridge with water to remove dried ink, but reusing it is not recommended. Cartridges are designed to be single-use, and reusing one risks leaks or poor ink flow. It is safer and cheaper to buy a new cartridge than to spend time trying to restore an old one.