Compiled from 4 sources; we haven't tested these products ourselves yet. How we research
Quick answer
The best fountain pen ink cartridges are the ones made for your pen: LAMY T10 for LAMY pens such as the safari, and Pilot's Namiki cartridges for the Metropolitan and Kakuno. A T10 holds 1.25 ml, a Pilot cartridge about 0.9 ml. To use bottled ink instead, fit LAMY's Z28 or Pilot's CON-40 converter.
On this page11 sections
Two cartridge systems and their converters; boxes in proportion, converters to scale at 1 mm = 3 px.
Pilot Namiki fountain pen ink cartridges, black, box of 12Pilot
Japan
Not stated*
Price range: $under $5 per item
LAMY Z 28 converter, red (item 1324763)LAMY
Germany
Germany*
Price range: $$$5–20 per item
Pilot CON-40 converterPilot
Japan
Not stated*
Price range: $$$5–20 per item
Notes on these facts
LAMY T 10 ink cartridges, black, box of 5: Made by C. Josef Lamy GmbH, Heidelberg (part of Mitsubishi Pencil Co., Ltd.). Made in Germany: LAMY's German quality page says it makes nearly all components in-house in Heidelberg, naming the LAMY ink cartridges, and its German ink guide says all LAMY inks are "Made in Germany" at the Heidelberg works. Source.
Pilot Namiki fountain pen ink cartridges, black, box of 12: Made by Pilot Corporation (Japan); sold in the US by Pilot Corporation of America. Country of manufacture not stated: Pilot Japan's web catalog lists ink type, box size, JAN and price for the IRF-12S-B but no country of manufacture, and Goulet Pens' listing doesn't give one either. Pilot is a Japanese company; we didn't find a page naming where the US-packaged Namiki box is filled. Source.
LAMY Z 28 converter, red (item 1324763): Made by C. Josef Lamy GmbH, Heidelberg (part of Mitsubishi Pencil Co., Ltd.). Made in Germany: LAMY's own Z 28 product listing (Ireland storefront) describes it as "Made in Germany", and LAMY's site says Heidelberg has been its only production site since 1930. LAMY's India product page, which gave Germany as the country of origin, has since been taken down. Source.
Pilot CON-40 converter: Made by Pilot Corporation (Japan); sold in the US by Pilot Corporation of America. Country of manufacture not stated: Pilot Japan's web catalog entry for the CON-40 lists size, capacity, JAN and price but no country of manufacture, and the Goulet Pens and Amazon listings we read don't give one either. Source.
Price bands are typical US retail, checked October 2026. Conversions to US dollars are approximate, at October 2026 rates (US$1 = ¥158 = ₩1,330 = NT$32.5 = CN¥6.7 = SEK 9.9 = DKK 6.7 = ₺49.6 = C$1.41 = A$1.43 = CZK 21.7; €1 = US$1.12; £1 = US$1.32; CHF 1 = US$1.21).
Key takeaways
LAMY says each T10 cartridge holds 1.25 ml, five to a box, in 7 colors; Goulet Pens lists about 0.9 ml for each of the 12 Pilot Namiki cartridges in a box.
Converters hold less than cartridges: about 0.8 ml for the LAMY Z28, per Goulet Pens, and 0.4 ml for the Pilot CON-40, per Pilot.
T10s fit every LAMY fountain pen except the piston-filling LAMY 2000; Pilot cartridges fit its cartridge pens except the Custom 823 and Custom Heritage 92.
LAMY and Pilot cartridges are proprietary: neither fits the other's pens, nor pens that take standard international cartridges.
LAMY's German shop lists a T10 box at €2.10 (about US$2.40), and Pilot Japan lists 12 cartridges at ¥550 (about US$3.50).
What are the best fountain pen ink cartridges?
The best cartridge is the one your pen takes: LAMY T10 for LAMY pens and Pilot’s own cartridges for Pilot pens, because neither fits the other. Both are cheap, clean and sold in black, blue and other colors. There’s no single #1, because a cartridge only fits its own brand of pen, so we pick by the pen you own.
For LAMY pens:LAMY T10. Why it’s here: the cartridge every LAMY cartridge pen takes, and at 1.25 ml it holds more than a Pilot cartridge (about 0.9 ml); five to a box in 7 colors, made in Heidelberg.
For Pilot pens:Pilot Namiki cartridges. Why it’s here: the only cartridge that fits current Pilot cartridge pens such as the Metropolitan and Kakuno; twelve to a US box, about 0.9 ml each per Goulet Pens.
Bottled ink in a LAMY:LAMY Z28 converter. Why it’s here: the converter LAMY lists for its plastic and aluminum pens, including the safari, with two lugs that lock into LAMY grips.
Bottled ink in a Pilot:Pilot CON-40 converter. Why it’s here: it fits most Pilot cartridge pens and has four metal agitators, though at 0.4 ml it holds less than a cartridge.
How did we choose these picks?
We compiled these picks from published sources, not hands-on testing: LAMY’s German shop and Pilot’s Japanese catalog for fit, capacity and price, Goulet Pens’ capacity figures, US availability and price band. Fit decided every pick, because a cartridge or converter that doesn’t fit your pen is no use at any price.
How do the cartridges and converters compare?
Cartridges hold more ink per fill; converters let you use any bottled ink.
LAMY T10
Pilot Namiki
LAMY Z28
Pilot CON-40
Type
Cartridge, 5 per box
Cartridge, 12 per box
Twist-piston converter
Twist-piston converter
Ink per fill
1.25 ml (LAMY)
About 0.9 ml (Goulet)
About 0.8 ml (Goulet)
0.4 ml (Pilot)
Fits
LAMY cartridge pens, not the LAMY 2000
Pilot cartridge pens, not the Custom 823 or Heritage 92
8 LAMY pens, incl. safari, AL-star, vista
Pilot pens such as the Metropolitan, Kakuno, Prera
Size
Box 38 × 8 × 71 mm (1.5 × 0.3 × 2.8 in)
Box 15 × 49 × 60 mm (0.6 × 1.9 × 2.4 in)
72 mm (2.8 in) long
60 mm (2.4 in) long
Maker’s price
€2.10 (about US$2.40)
¥550 (about US$3.50)
€5.90 (about US$6.60)
¥550 (about US$3.50)
Made in
Germany
Not stated
Germany
Not stated
Band
$
$
$$
$$
Specs and prices are from LAMY’s German shop and Pilot’s Japanese catalog, with capacities from LAMY, Pilot and Goulet Pens.
A T10 holds about three times as much ink as a CON-40.
Which pens do LAMY and Pilot cartridges fit?
T10s fit every LAMY cartridge fountain pen, and Pilot cartridges fit every current Pilot cartridge pen; neither fits other brands. LAMY lists the exception as the LAMY 2000, a piston filler, and Pilot names the bottle-filling Custom 823 and Custom Heritage 92.
Goulet Pens’ chart lists Kaweco, Pelikan, TWSBI, Visconti, Monteverde and Faber-Castell as taking standard international cartridges, and Pilot, Platinum, Sailor, LAMY, Parker and Cross as proprietary. Our guide to filling a fountain pen explains each system.
Should you use cartridges or a converter?
Start with cartridges, and add a converter once you want bottled ink. A cartridge clicks in with no mess and carries more ink, which suits travel and school.
A converter opens up every bottled ink and costs less per fill over time. The trade-off is capacity: Pilot says a CON-40 that looks half full after a 0.4 ml fill is normal, and Goulet reviewers call that capacity small.
Which converter fits which pen?
The Z28 fits LAMY’s plastic and aluminum pens, and the CON-40 fits most Pilot cartridge pens. LAMY’s German site lists the Z28 for the abc, safari, vista, joy, AL-star, Lx, nexx and nexx M; two guide lugs lock it into their grips.
The CON-40 suits the Pilot Metropolitan, Kakuno and Prera; some pens, such as the Kakuno, also take the bigger CON-70. For a LAMY, see our LAMY safari guide.
Can you refill a used cartridge?
Yes: rinse it, fill it with a blunt syringe and push it back on. That gives a Pilot or LAMY pen bottled ink without a converter, and a refilled T10 still holds 1.25 ml.
Both makers’ cartridge inks are water-based dyes, and Goulet lists the black LAMY and Pilot cartridges as not water resistant. For a sturdier bottled ink, see our best fountain pen inks.
Where are they made?
LAMY makes T10 cartridges and the Z28 in Heidelberg, Germany, its only production site. LAMY’s Z28 listing says Made in Germany.
Pilot’s Japanese catalog lists sizes and prices for its cartridges and the CON-40 but not a country of manufacture.
Frequently asked questions
Do LAMY cartridges fit Pilot pens?
No. LAMY T10 and Pilot cartridges are both proprietary, with different shapes, so each fits only its own maker's pens.
Do all fountain pens use the same cartridges?
No. Many European brands, such as Kaweco, Pelikan and TWSBI, take standard international cartridges, while Pilot, Platinum, Sailor, LAMY, Parker and Cross use their own, per Goulet Pens' chart.
How long does a fountain pen cartridge last?
It depends on the nib and how much you write; a 1.25 ml T10 lasts longer than a 0.9 ml Pilot cartridge with the same nib. Neither maker publishes a page count.
Is a converter better than cartridges?
A converter lets you use any bottled ink and costs less per fill over time, but it holds less: about 0.8 ml for the LAMY Z28 and 0.4 ml for the Pilot CON-40. Cartridges are cleaner to carry and quicker to change.
Can you refill an ink cartridge with bottled ink?
Yes. Rinse the empty cartridge, fill it with a blunt syringe and push it back on. A refilled cartridge gives a cartridge-only pen any bottled ink.
Are LAMY T10 and Pilot cartridge inks waterproof?
No. Both are water-based dye inks, and Goulet Pens lists the black LAMY and Pilot cartridges as not water resistant.
Where are LAMY and Pilot cartridges made?
LAMY says it makes its cartridges and converters in Heidelberg, Germany. Pilot doesn't state where its cartridges or the CON-40 are made.
LAMY T 10 ink cartridges, black, box of 5
Pilot Namiki fountain pen ink cartridges, black, box of 12
LAMY Z 28 converter, red
Pilot CON-40 converter