Guides
Fountain pen cartridge and converter compatibility
There is no universal cartridge. Buying the wrong one is the most expensive small mistake in this hobby, and there is no adapter.
Cartridges by brand
| Brand | Cartridge type | Notes |
|---|---|---|
| Pilot | Pilot proprietary (IC-100 and equivalents) | Fits the Metropolitan, Kakuno, Prera and most others. |
| LAMY | LAMY T10, proprietary, 1.25 ml | Fits every LAMY fountain pen. Nothing else does. |
| Platinum | Platinum proprietary | Includes the pigment Carbon Black cartridge. |
| Kaweco | International standard, SHORT only | The Sport barrel will not take a long cartridge. |
| Jinhao | International standard | Most models ship with a converter too. |
| Faber-Castell | International standard | Sold as standard ink cartridges. |
| Monteverde, Diamine, J. Herbin | International standard | Third-party colors for any standard pen. |
Converters by brand
| Converter | Fits | Does not fit |
|---|---|---|
| LAMY Z28 | LAMY ABC, AL-star, joy, Lx, nexx, nexx M, safari, vista | Older LAMY models that take the Z24; anything non-LAMY |
| Pilot CON-40 | Pilot pens with a narrow barrel, including the Metropolitan and Kakuno | Pens that require the wider CON-70 |
| Pilot CON-70 | Pilot pens with a barrel wide enough to accept it | The Metropolitan, Kakuno and Prera |
| Kaweco Sport mini | Kaweco Sport, 0.47 ml capacity | Full-size pens; anything non-Kaweco |
| International standard converter | Most pens that accept international standard cartridges | Pilot, LAMY, Platinum |
Quick picks
Ranked for the beginner buying their first setup. Every pick names who it is wrong for.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | No image LAMY Z28 converter The piston converter that turns any modern LAMY cartridge pen into a bottled-ink pen. | Bottled ink in a Safari, AL-star or Vista | Check price on Amazon #ad No live price right now. How this is funded |
| 2 | No image Pilot CON-40 converter The screw converter that fits the widest range of Pilot pens, including the ones with narrow barrels. | Bottled ink in a Metropolitan or Kakuno | Check price on Amazon #ad No live price right now. How this is funded |
| 3 | No image Pilot CON-70 converter A push-button vacuum converter that holds noticeably more than the CON-40, for pens wide enough to take it. | The largest ink capacity Pilot offers in a converter | Check price on Amazon #ad No live price right now. How this is funded |
| 4 | No image Kaweco Sport mini converter The only converter short enough for a Sport barrel, holding 0.47 ml — which is genuinely not much. | Bottled ink in a Kaweco Sport | Check price on Amazon #ad No live price right now. How this is funded |
1. Bottled ink in a Safari, AL-star or Vista
LAMY Z28 converter
The piston converter that turns any modern LAMY cartridge pen into a bottled-ink pen.
#ad No live price right now. How this is funded
Buying a Safari without a converter is the most common first-order mistake in this hobby. The pen ships with one cartridge and no way to use bottled ink.
The Z28 is a twist piston: put the nib in the bottle up to the section, twist, and it draws ink. There is no trick to it.
Check the number. The Z24 looks nearly identical and fits a different set of pens.
| Fits | LAMY ABC, AL-star, joy, Lx, nexx, nexx M, safari and vistaSource: LAMY Z28 converter (retail listing, read 2026-09-01) |
|---|---|
| Type | Piston converterSource: LAMY Z28 converter (retail listing, read 2026-09-01) |
| Capacity | Not published |
| Not to be confused with | The Z24, which fits older LAMY modelsSource: LAMY Z24 converter (retail listing, read 2026-09-01) |
What it does well
- Fits the whole current LAMY range
- Simple twist piston with nothing to break
- Turns a cartridge pen into a bottle pen for a few dollars
What it does not
- Holds less ink than a T10 cartridge in practice
- Easy to confuse with the Z24
- LAMY-only
Skip this if you only ever use cartridges — it is a part you will never fit.
2. Bottled ink in a Metropolitan or Kakuno
Pilot CON-40 converter
The screw converter that fits the widest range of Pilot pens, including the ones with narrow barrels.
#ad No live price right now. How this is funded
Pilot sells several converters and they are not interchangeable. The CON-40 is the small one that fits nearly everything; the CON-70 holds far more but only fits wider pens.
The CON-40 has agitator balls inside it, which look like a defect and are not — they stop ink clinging to the walls.
If you own a Metropolitan and want to use a bottle, this is the part.
| Type | Screw-type converterSource: Pilot CON-40 converter (retail listing, read 2026-09-01) |
|---|---|
| Fits | Pilot fountain pens that take the CON-40, including the Metropolitan and KakunoSource: Pilot CON-40 converter (retail listing, read 2026-09-01) |
| Capacity | Not published |
| Larger alternative | The CON-70, for pens with a wider barrelSource: Pilot CON-70 converter (retail listing, read 2026-09-01) |
What it does well
- Fits the widest range of Pilot pens
- Cheap enough to buy two
- Screw fitting will not fall out
What it does not
- Small capacity
- Not interchangeable with the CON-70
- Pilot does not publish the capacity
Skip this if your Pilot takes the larger CON-70 — buy that instead and get double the ink.
3. The largest ink capacity Pilot offers in a converter
Pilot CON-70 converter
A push-button vacuum converter that holds noticeably more than the CON-40, for pens wide enough to take it.
#ad No live price right now. How this is funded
The CON-70 fills by pressing a button repeatedly, which pulls ink in by vacuum. It holds far more than the CON-40 and is the reason some Pilot owners never think about refilling.
It only fits pens with the barrel width to take it. Check before buying — a CON-70 in the wrong pen simply will not close.
Pilot does not publish a capacity figure for either converter, so we do not quote one.
| Type | Push-button converterSource: Pilot CON-70 converter (retail listing, read 2026-09-01) |
|---|---|
| Fits | Pilot pens with a barrel wide enough for the CON-70Source: Pilot CON-70 converter (retail listing, read 2026-09-01) |
| Capacity | Not published |
| Smaller alternative | The CON-40, which fits narrower barrelsSource: Pilot CON-40 converter (retail listing, read 2026-09-01) |
What it does well
- Much larger capacity than the CON-40
- Push-button filling is quick
- Fewer refills means fewer chances to make a mess
What it does not
- Does not fit narrow-barrelled Pilot pens
- Harder to clean than a piston converter
- No published capacity
Skip this if your pen is a Metropolitan, a Kakuno or a Prera — those take the CON-40.
4. Bottled ink in a Kaweco Sport
Kaweco Sport mini converter
The only converter short enough for a Sport barrel, holding 0.47 ml — which is genuinely not much.
#ad No live price right now. How this is funded
Kaweco publishes the capacity, and the number is the argument: 0.47 ml is less than a short international cartridge. A pocket pen has a pocket-sized barrel and there is no way around it.
If you want to use one specific bottled ink in a Sport, this is the only way to do it.
For most people the honest answer is to use cartridges in the Sport and save bottled ink for a bigger pen.
| Capacity | 0.47 mlSource: Kaweco Sport mini converter (retail listing, read 2026-09-01) |
|---|---|
| Fits | Kaweco Sport fountain pensSource: Kaweco Sport mini converter (retail listing, read 2026-09-01) |
| Use | Made for use with bottled inkSource: Kaweco Sport mini converter (retail listing, read 2026-09-01) |
| Type | Not published |
What it does well
- Published capacity, which almost no converter maker offers
- The only way to use bottled ink in a Sport
- Fits without modification
What it does not
- 0.47 ml is very little ink
- Costs a meaningful fraction of the pen
- Refilling becomes a frequent chore
Skip this if you write more than a page a day in the Sport — you will spend more time filling than writing.
Short and long: the second trap
International standard cartridges come in two lengths, and they are genuinely different parts. A long cartridge holds roughly twice a short one; a pocket pen like the Kaweco Sport takes only the short version.
Full-size pens usually accept either, and many will hold a spare short cartridge in the barrel behind the one in use — a small convenience that is worth knowing about.
How to check before you buy
- Identify the pen brand. If it is Pilot, LAMY or Platinum, buy that brand's part and stop reading.
- Otherwise, assume international standard, which is what most European and Chinese pens use.
- Check the barrel length. A short pocket pen needs a short cartridge.
- For a converter, check the specific model. Pilot in particular has several that are not interchangeable, and the CON-70 will not close in a narrow barrel.
There is no adapter
This comes up often enough to state plainly: there is no reliable adapter that lets an international standard cartridge fit a Pilot, LAMY or Platinum pen. The nipple diameters and lengths differ, and a forced fit leaks.
If you want ink freedom in one of those pens, the answer is that brand's converter and a bottle — which is the argument made in cartridge vs converter.
Questions people actually ask
Do all fountain pens use the same cartridges?
No. Pilot, LAMY and Platinum each use a proprietary cartridge that nothing else fits. Most other brands take the international standard, which itself comes in short and long lengths.
Which converter fits a LAMY Safari?
The LAMY Z28, which also fits the AL-star, joy, Lx, nexx, nexx M, vista and ABC. The older Z24 fits different models and is easy to confuse with it.
What is the difference between the Pilot CON-40 and CON-70?
Capacity and fit. The CON-40 is the small screw converter that fits narrow barrels including the Metropolitan and Kakuno; the CON-70 is a larger push-button converter that only fits wider pens.
Can I use an adapter to fit standard cartridges in a Pilot pen?
No. There is no reliable adapter — the nipple dimensions differ and a forced fit leaks. Use a Pilot converter and bottled ink instead.
What is the difference between short and long international cartridges?
Length and capacity: a long cartridge holds roughly twice a short one. Pocket pens such as the Kaweco Sport only accept the short version.
Sources
- LAMY Z28 converter — fits list (retail listing, read 2026-09-01)
- LAMY Z24 converter (retail listing, read 2026-09-01)
- Pilot CON-40 converter (retail listing, read 2026-09-01)
- Pilot CON-70 converter (retail listing, read 2026-09-01)
- Kaweco Sport mini converter — 0.47 ml (retail listing, read 2026-09-01)
- LAMY T10 cartridges — 1.25 ml (retail listing, read 2026-09-01)