Ballpoint Pen Refill Types and How to Choose One

Why refill types are not interchangeable

Many pens can be refilled instead of thrown away, but a refill from one pen will often not fit another. Refills differ in length, diameter, tip shape and the way they are held in the barrel. Some follow a common standard that many makers use, and others are made only for one brand’s pens.

The good news is that a handful of refill types cover most pens. Once you can recognize those, choosing a replacement is mostly a matter of matching shape and size, then picking the ink and tip you prefer.

The common refill types

Lengths vary slightly between sources and makers, so use these as a guide and compare against your actual refill.

Parker-style (G2) refills

The Parker-style refill is one of the most widely used. It combines a good ink capacity with a modest size, and it has a recognizable look: a long thin tip, a wider barrel and an end piece with grooves. Despite the name, it is officially known as G2, which is why people say “Parker-style” to avoid confusion with the Pilot G2 gel pen refill, which is a different shape.

Parker-style refills are usually metal, though some are plastic. They are mostly ballpoint ink, with some gel options, and they are generally interchangeable between pens. One occasional problem is that very broad refills (over 1.0 mm) can have tips too large to pass through the opening of some pens.

D1 refills

D1 refills are short, slim and smooth, often made entirely of metal. They are common in multi-function pens and pocket-size pens. Most D1 refills are ballpoint, though a few use gel ink. Gel D1 refills can run out quickly because of their small size.

Most D1 refills are interchangeable, with one known exception: Zebra’s are reported to be slightly wider, so another brand’s D1 refill may fit loosely in a Zebra pen.

Cross-style (C1) refills

Cross-style refills are long, slender tubes, typically with a threaded or knurled knob at the rear. The C1 designation covers a family of similar refills, and the exact length varies by maker. Several third-party brands make substitutes. If you own a classic slim metal pen, check whether it uses a C1-type refill.

Japan type refills

Japan type refills usually have a plastic body of around 3 mm diameter and are often 100 mm or longer, but there are many exceptions. They are common in everyday click pens and cap pens, including pens sold in stationery shops. Because lengths vary, compare the old refill against the replacement and check its description rather than assuming a match.

Retractable-pen standards (A2, X20, G1)

Retractable pens often use refills with a small spring shoulder, which may be a crimp or wing that holds a spring in place. International standards such as A2, X20 and G1 describe different tip and shoulder positions even though the overall length is similar. Because the shoulder sits at a different place on each, a refill that looks right may sit incorrectly in the pen. Look for the standard name in your pen’s markings or manual.

Proprietary refills

Some makers use refills made only for their own pens. Examples include Lamy, Montblanc and Waterman. In some cases, third-party refill makers also produce a compatible version, but it is often best to start with the manufacturer’s refill if you can find it.

Ink types: oil-based, hybrid and gel

• Oil-based ballpoint ink. The traditional choice. It dries quickly, resists smudging and lasts a long time, though it requires slightly more pressure to write.
• Hybrid ink. A blend that aims for the longevity of ballpoint ink with a lower-pressure, smoother feel closer to gel.
• Gel ink. Water- or pigment-based. It offers bold colors and a very smooth glide, but usually takes longer to dry and tends to be used up faster.

If you are weighing how a ballpoint compares to a pen with liquid ink, see our guide to ballpoint vs fountain pen.

Tip size

Refills are commonly sold in three rough size bands:

• Fine: about 0.5 to 0.7 mm
• Medium: about 0.7 to 1.0 mm
• Broad: above 1.0 mm

Finer tips give smaller, more detailed writing and are often chosen for notebooks and planners, including bullet journals (see the best pen for bujo). Broader tips give bolder lines and often feel smoother, though they use ink faster.

How to find the right refill for your pen

Try these methods in order:

1. Check the old refill. Many have a brand or model printed on the barrel. Use this to search for an exact replacement.
2. Check the pen. Look for the refill name or standard in the packaging, the manual or the manufacturer’s website.
3. Measure and compare. If the first two fail, measure the refill’s length, diameter and tip shape, and compare them to product pages. This is the least reliable method, because many refills look alike but differ in small ways.

Manufacturers sometimes use similar model numbers for different refills, so a web search by pen name can return the wrong one. Always compare photos and specifications.

Adapters, springs and other small parts

Some refills are held in place by an adapter or spacer. If your original refill seems to be made of more than one part, gently pull it apart and keep any small pieces safe, because you may not be able to get a replacement. Similarly, if your pen has a spring near the tip that comes out when you remove the refill, keep it, since most replacement refills do not come with one.

How do I know which refill to buy?

A quick checklist:

• Identify the refill type from the table above.
• Match the length and the shape of the tip and rear end.
• Choose an ink type: oil-based for durability, gel for smoothness, hybrid for a balance.
• Pick a tip size that suits your writing.
• Keep any adapters or springs from the old refill.

If you would like a pen that avoids refills altogether, take a look at the most popular fountain pens.