Why a Multifunction Pen Is the Only Pen an Adult Needs

If you spent your high school years hovering over glittery gel pens and mechanical pencils, you probably ended up in one of two camps: you either stopped using pens entirely but still buy novelty stationery, or you've sworn off new purchases and are slowly burning through a decade-old stash. I'm in both camps. And it wasn't until I started juggling both that I realized how different "student stationery" is from "adult stationery." The multipen—that most useless category during my school days—has become the only pen I keep in my bag and on my desk.

Multipens, also known as multi-pens or multifunction pens, are exactly what they sound like: several pen refills stuffed into a single barrel. The idea is to shrink the total volume of what you carry, so one tool covers all your writing needs. If you were born before 2000, you probably remember the first wave of these—those chunky multicolor ballpoint pens with eight or ten colors crammed into one body. Kids who liked to draw could color an entire picture with a single pen.

Why Multipens Make Sense for Adults

For students, multipens are a terrible deal. Because the barrel has to hold multiple refills, each refill is thinner and holds less ink. And since most schools require water-based ink for exam papers, you'd blow through a $15 pack of refills in a day. But once you're working—or even in college—your daily writing volume drops dramatically. You no longer need a pen that lasts a month; you need one that lets you switch between colors or functions instantly. That's where multipens shine.

The Big Brands, Broken Down

Budget Chinese Multipens

If you search "multipen" on any shopping site, you'll mostly see Chinese brands. Miniso, KKV, and other lifestyle stores often stock these, usually made by companies like Aihao, Deli, or Kaco. They're cheap, they work, and the main differences are print quality and build consistency. The one common issue is the threading on the barrel—some models loosen on their own. So if you can, try them out in a physical store before buying.

LAMY: Design First

LAMY, the German brand known for its design (and recently acquired by uni), offers multipens in four series: st, logo, cp1, and 2000. The st and cp1 use a rotating mechanism that clicks through colors, and both include a mechanical pencil module. The 2000 and logo use a gravity-based system where you point the color you want upward and press a single button. It's not fast, but it looks elegant. For office workers who only occasionally need a red underline, it's fine. For students, it's a no-go.

Pilot: The Coleto System

Pilot's Coleto is the most customizable multipen out there. The refills snap in with a satisfying "click"—the name actually comes from that sound. You can build a pen with anywhere from two to five modules, and the refill selection is insane: 0.3mm, 0.4mm, and 0.5mm gel ink in 33 colors (including fluorescent, metallic, and pastel), plus mechanical pencil and eraser modules. They also do limited-edition collabs with anime and other IPs, so if you're a collector, beware.

Pentel: Understated but Solid

Pentel isn't the first name in multipens, but they make some of the best ink. Their i+ system is modular—you buy the barrel and refills separately—and it's compatible with Energel (their fast-drying gel ink) and Sliccies (their colored gel line). The i+ barrels are transparent at the bottom, so you can see the refill color. They even have a spot on top for a headphone-jack dust plug, which is a nice throwback. Pentel also makes the Multi 8, a rare 8-color colored-pencil multipen that uses 2.0mm leads—perfect for drafting or sketching if you can find it.

uni: The Multipen King

uni (Mitsubishi Pencil) makes a multipen for every series they have. The two big ones are Style Fit (gel) and Jetstream (oil-based ballpoint). The Jetstream ink is legendary—smooth but not slippery, with a nice controlled feel. It's the standard for oil-based multipens. Hobonichi planners even include a custom Jetstream multipen as a freebie every year. Style Fit offers three-to-five-module barrels, plus a single-module version that's mainly for testing colors. Refills come in 0.28mm, 0.38mm, and 0.5mm, with 16 standard colors.

Refill Compatibility: The Real Game

Here's where multipens get tricky. Most refills fall into two standards:

• ISO D1: 2.3mm thick, 67mm long, usually metal. European brands like LAMY use these.
• Japanese standard: 3mm thick, length varies (88mm or 98mm). Pilot, Pentel, and uni all use variations of this.

For example, Pilot Coleto refills are 93mm long (without the button), while Pentel Sliccies and uni Style Fit are 98mm. The uni Jetstream, however, is 88mm—the same as most Chinese multipen refills, which is why it's so easy to find cheap alternatives.

Zebra is a mess: they have NJK (3.0mm), JK (3.5mm), and even D1-compatible refills, all incompatible with each other. Unless you love their Sharbo design or the ink feel, skip them.

Should You Buy Third-Party Refills?

Original refills are expensive, especially if you write a lot in black or blue. But because of these standards, you can often find compatible refills for a fraction of the price. Just make sure you check the diameter and length. If you're not sure where to start, the Pilot Coleto is the most versatile, and the uni Jetstream has the best writing feel with the most affordable alternatives.

So next time you're staring at your overflowing pen cup, consider consolidating. A single multipen might be all you need.