Muji Fountain Pen Review

muji fountain pen review

We were always told not to judge a book by its cover, with this Muji fountain pen review, we had to put that idiom to the test. What, at first glance, appears to be nothing more than an ordinary aluminum pen turned out to be one of the biggest surprises of the year. 

To get a better understanding of this Japanese fountain pen, we put it to the test and wrote hundreds of lines of text to see how it fared against similar offerings in the same price range.

We also assess it in terms of its appearance, performance, and accessibility to see how this Muji fountain pen works for a general audience.

Muji Aluminum Fountain Pen (Our Review)

MUJI Aluminum Body Fountain Pen - Fine Nib - with 1 Black Ink Refill Cartridge
  • Weight: 20g
  • Compatible ink cartridges: Muji 5-139040 (5-139040)
  • Made in Japan
  • Dimensions: total length 13.7 cm (with cap), diameter 1cm

Overall Assessment

With Japanese fountain pen brands, you can always expect something a little special. Muji aluminum fountain pens are no exception.

While it doesn’t necessarily compare to the grandiosity of some premium brands like Parker or Montblanc, there’s a lot to be appreciated about the design. 

It has a sleek profile, and just by looking at the diamante-textured grip, you can tell that the pen’s going to be comfortable to hold. If you’re looking for something to display on a shelf rather than to use regularly, this pen is not for you.

If you’re an everyday writer or note-jotter, Muji Aluminum fountain pens are a great choice. The cartridges are interchangeable, meaning you won’t have to get a new pen when the ink has been used up. This makes Muji fountain pens cost-efficient.

Included in the box, you get a cartridge of black ink for when your pen runs dry. The Muji fountain pen is compatible with any standard international converter, so it won’t be a mission to replace them. 

Some of Muji’s product pages suggest that short standard international cartridges or also acceptable, but we need to stress that this isn’t necessarily the case. The short standard converter option is only for the pocket-sized version of this pen, which Muji doesn’t always make clear.

Ink flow is steady, so you don’t have to worry about feathering or smudging, provided you’re using quality ink


  • Lightweight but durable
  • Low maintenance
  • Budget-friendly
  • No bleeding or feathering
  • Worldwide shipping


  • Plain design
  • Converter sold separately
  • Cheap plastic packaging

Detailed Analysis

We take a closer look at some of the key features of the Muji aluminum fountain pen in the sections below.


Like all Muji stationery, the fountain pens have a simple design. Its plain cylindrical shape doesn’t do much to grab your attention. The uniform silver body makes the pen disappear into the background and doesn’t leave much of an impression.

If the cap didn’t have a clip, you’d be forgiven for mistaking it as a mascara wand.

The Schmidt nib, on the other hand, is a little more exciting. The steel nib is exquisitely engraved with the company’s logo and branding so you’re constantly reminded of its quality.

There’s some debate around here about whether it’s enough to make up for the bland design, or even if it does more harm than good. There’s definitely a bit of a disconnect between the spartan exterior and the frilly nib etching.

Posted, the pen is about 5.5 inches long. This could be an issue for anyone with larger hands, although the rough grip section will help a lot with that.

Weight and Durability

The aluminum body on the Muji fountain pen is a bit of a double-edged sword. On one hand, it’s a lightweight, durable, and inexpensive material that makes for a great writing utensil. 

On the other, the pen’s lack of any substantial weight does mean you have to press a bit harder to get ink to flow, which could result in tired hands or even repetitive strain injuries after extended periods of writing.

It weighs just over 0.7 oz, so it’s lighter than even some disposable, plastic fountain pens. If you’re used to using dense-bodied fountain pens made from wood, steel, or ivory, it’s going to take some getting used to. 

One of the many upsides of the design is that’s it’s incredibly durable and resilient. Because aluminum is a less brittle metal, there’s a little bit of spring in the body. This means it can survive a few drops and tumbles without always picking up dents and scratches.

It’s also not going to weather as quickly as wood or ivory. Aluminum can withstand a little bit of moisture without the metal tarnishing. What’s more, the heavy particulates in the ink won’t damage the nib, as the iridium point is specially incorporated to repel any corrosion.


The ink flow from the cartridge to the nib is instant and consistent, making it an absolute dream to write with. 

Using this fountain pen with quick, determined strokes will make handwriting easier and more enjoyable. Once you get the hang of it, you can even begin to incorporate some more advanced writing techniques like serifs, italics, and even calligraphy.


As the nib is made from steel, it’s not the most flexible option on the market. That’s not to say that it’s entirely rigid, only that you don’t have as much give as a gold or platinum-plated nib.

Overcoming that first bit of resistance in the nib can be a bit nerve-wracking though. It can feel like the nib is about to bend or break, especially when it’s brand new. You just have to push past it until the metal softens up a little.

While it’s sturdy, the pen still has to be handled with care. You should always make sure that you clean your pen out every couple of weeks to detach any solid particulates that are floating around in the inner mechanisms.

If you’re not using your fountain pen regularly, you should consider draining the ink before packing it away.

Unfortunately, owing to the design of the pen, the nibs aren’t interchangeable, so you’re stuck with a fine nib whether you want one or not.

Fine-nib pens are best for people with small handwriting, as the lines are small enough to leave good definition between the strokes of each character. If you’re the kind of person whose handwriting spills onto the margins of the page, the thin lines could make your text disappear into the page a bit.

It glides over the paper smoothly, allowing you to use quick, confident strokes. You get the pleasant scratching sound typical of writing with a fountain pen, and the low pressure needed to draw ink means you’re not likely to tear the page.


One of the best things about Muji Fountain Pens is that they are affordable. 

For an experience and quality that could normally cost you well over $100, you can get a Muji fountain pen for between 15 and $20. 


There’s definitely lots of debate in the community about whether Muji fountain pens live up to their hype. We’re certainly not going to die on the hill that the Muji fountain pen is the best in the known universe, but for what’s on offer and how much it costs, you could do a lot worse.

While the pen isn’t the most exciting thing to look at, there’s something almost calming about its toned-down aesthetic, and we appreciate that the brand is sticking to their guns and making the pens that they want to make.

If you’re looking for that workhorse fountain pen to add to your arsenal that will get you through long days of taking notes and scribbling doodles, this pen might just be the one for you.

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