Ink cartridges: a complete guide to choosing and buying

Buying an ink cartridge ought to be trivial. It isn't. Between alphanumeric codes that change by region, chips with firmware that blocks third-party consumables and prices ranging from €8 to €60 for the same slot, restocking a consumable is more like deciphering a hieroglyph. This guide cuts through the noise: which code your printer is looking for, when a compatible performs the same as the original, what protects you legally and how to stretch each cartridge 20%-40% further.

Key points
- The code printed on the cartridge (304, PG-545, 603XL, LC3213) is your universal identifier, and works the same for original and compatible.
- An XL cartridge holds 2.5-3 times more ink but costs only 60%-80% more: the cost per page falls almost by half.
- Reputable compatibles work out between 40% and 75% cheaper per page than the OEM (Consumer Reports, 2024).
- Using compatibles does not void your printer's warranty in the EU (Directive 2019/771).
- Yield is measured with the ISO/IEC 24711 standard; always compare that figure, not the one on the box.

We sell compatible consumables and print them before putting them on sale, so what follows is the same as we tell a customer who calls with questions before paying. If you're not yet clear whether your machine uses ink or toner, start with cartridge or toner: which to choose.

What is an ink cartridge and how does it work?

An ink cartridge is a sealed reservoir that feeds the print head of an inkjet printer. Three parts work inside: the ink chambers (watertight reservoirs that isolate cyan, magenta and yellow to avoid chromatic contamination), the injector nozzles (between 100 and several thousand micro-nozzles that fire drops of 1-10 picolitres) and an EEPROM chip that talks to the firmware and reports level, model and date.

That chip decides a lot of the game. In an original cartridge it blocks reuse; in a well-made compatible it replicates the dialogue with the printer so the machine recognises it as valid. When a printer "can't see" a compatible, it's almost always the chip or a firmware update, not the ink. If it happens to you, the solution is in my printer doesn't recognise the compatible toner.

XL versus standard: the decision that saves the most

An XL cartridge contains between 2.5 and 3 times more ink than its standard version in an almost identical casing, but the price only goes up 60%-80%. The result: the cost per page falls almost by half. The trap is comparing "box pages" between brands, because not all of them measure the same way. Reliable yield is calculated with the ISO/IEC 24711:2021 standard, which prints a set of pattern pages to the cartridge's end of life under controlled conditions. Always compare that ISO figure, or the millilitres directly.

Rule of thumb: if you print more than 40 pages a month, the XL pays for itself in a single cycle. Below 15 pages a month, the standard prevents the ink from drying out before it's used. For specific numbers by model, see how many pages a cartridge prints.

Compatibles or originals? The truth without the marketing

For home and office use, a reputable compatible cartridge prints the same as the original and costs considerably less. The price difference doesn't fund better ink: it funds the razor & blade model, a cheap printer and an expensive consumable. Consumer Reports illustrates it with an HP 27 cartridge that costs $31 on the official site versus $11 in a compatible version, and estimates the per-page saving of reputable compatibles at between 40% and 60% (Consumer Reports, 2024).

The Achilles' heel of the compatible sector is variability: there are manufacturers that clone the chip well and fine-tune the ink, and others that bottle just about anything. Consumer Reports warns in 2024 that it doesn't score third-party inks because the market is so fragmented and changeable that a direct comparison is impossible. Translation: the seller's brand matters as much as the price. (Consumer Reports, 2024)

That's why we print batches of every reference before selling it: density, bleed in blacks and chip recognition. The compatibles that pass that test are indistinguishable by eye in an office document; the ones that fail never make it off the bench. The real difference lies in the quality control of whoever sells it to you, not in the "compatible" label.

Parameter	Original (HP 304XL black)	Reputable compatible
Indicative price	€32-€38	€9-€14
ISO/IEC 24711 yield	~480 pages	~480-520 pages
Optical density	High	Almost identical
Firmware recognition	Native	Updated chip
Saving per page	—	40%-75%

If you want the breakdown of cents per page, it's in the real cost of printing. And if you're weighing up this debate for laser, we did it live in original vs compatible toner, printed side by side.

How do I choose the right cartridge in three steps?

You need two pieces of data: your printer's exact model and the code printed on the installed cartridge. With those you always get it right, both for original and compatible. It's a three-step process that takes less than a minute.

1. Identify the exact model. "HP DeskJet" isn't enough: you need the full suffix (DeskJet 3750, OfficeJet Pro 9014e). It's on the label on the back of the machine or under Settings → Device information. A single-digit difference cancels compatibility. Detailed guide in how to know which toner your printer needs.
2. Locate the cartridge code. Open the top lid: the active cartridge has a short code printed on it (304, 603XL, PG-545, LC3213). That code is your universal identifier.
3. Decide on capacity. More than 40 pages/month → XL. Fewer than 15 → standard. The XL sweet spot is between 20 and 40 pages a month.

If you suspect a marketplace cartridge isn't what it says, be careful: compatible and counterfeit are not the same. The difference, with photos, in counterfeit vs compatible.

How do you decipher the codes by brand?

Each manufacturer uses its own nomenclature, and understanding it stops you ordering the wrong cartridge. With these four systems you cover HP, Canon, Epson and Brother, which are the vast majority of the domestic inkjet fleet in Spain. You just need to recognise the prefix and the capacity suffix.

HP: a 2-4 digit number + XL suffix

HP labels with a short number (301, 304, 364, 903, 953) and adds XL for high capacity. The low series are domestic; the 900 series are the professional OfficeJet Pro range.

• HP 304 / 304XL → DeskJet 2620, 2630, 3720, 3730
• HP 305 / 305XL → DeskJet 2710, 2720e, 4110e; Envy 6010, 6020
• HP 903 / 903XL → OfficeJet Pro 6960, 6970, 6975
• HP 953 / 953XL → OfficeJet Pro 7720, 8210, 8710

Compatible catalogue in ink cartridges.

Canon: PG / CL / PGI / CLI prefixes

Canon separates pigmented black and colour into two cartridges and uses the prefix to indicate technology and segment: PG- (pigment black, domestic PIXMA), CL- (tricolour CMY), PGI- and CLI- (individual, Maxify and semi-pro PIXMA).

• PG-540 / CL-541 → PIXMA MG2250, MX475
• PG-545 / CL-546 → PIXMA TS3150, TS3350, MG2550S
• PGI-570 / CLI-571 → PIXMA MG5750, TS5050

Epson: number + iconographic family

Epson identifies the series with a number and christens each family with an icon ("strawberry", "binoculars", "pineapple", "starfish") that marks the regional compatibility. They aren't decorative: they help you filter in the shop.

• Epson 502 / 502XL ("binoculars") → Expression XP-5100, XP-5105; WF-2860
• Epson 603 / 603XL ("starfish") → XP-2100, XP-3100, XP-4100; WF-2810
• Epson 604 / 604XL ("pineapple") → XP-2200, XP-3200; WF-2910, WF-2930
• 664 / 774 → EcoTank (bottles, not cartridges)

If your machine is a tank model, compare them in EcoTank vs MegaTank vs Smart Tank.

Brother: LC prefix + number + capacity

Brother uses LC (Liquid Cartridge) plus a series number; the XL suffix multiplies the usable capacity.

• LC3211 / LC3213 → DCP-J572DW, MFC-J890DW, MFC-J895DW
• LC3217 / LC3219XL → MFC-J5330DW, MFC-J5730DW, MFC-J6530DW
• LC3235XL / LC3237 → DCP-J1100DW, MFC-J1300DW

Universal XL rule. When you see XL or XXL, the cartridge fits physically the same as the standard; it's the firmware that decides whether it charges you as XL or only delivers the standard yield. When in doubt with a specific model, ask before buying.

Can firmware block my compatible cartridge?

Yes, and it's worth knowing before you accept an update. For years HP has applied a function called Dynamic Security that, via firmware, can reject cartridges with a non-HP chip. In March 2023 an update again blocked third-party ink on OfficeJet models, going from an ignorable warning to a total block on some machines (Gizmochina, 2023).

There's room to defend yourself. After several class actions in the US, HP agreed to allow owners of a list of models to reject updates with Dynamic Security and even reverse blocks already installed by means of a firmware downgrade (abit.ee, 2024). In practice: if your printer is an HP and works with compatibles, disable automatic updates. How to do it, step by step, in HP firmware that blocks cartridges. And if you're weighing up the official subscription, read about it first in HP Instant Ink in Spain.

Is it worth refilling cartridges?

Refilling is tempting (a 100 ml bottle costs €8-€12 and refills several cartridges) but it only works well in cartridges without an integrated head, like Canon PGI/CLI or Epson 26/33. In those that carry the head inside (most cheap HPs: 304, 305, 364), the head degrades with each cycle and, after two or three refills, quality collapses. What's more, refilling voids the metering chip, so you lose the ink level.

When yes: low-demand internal drafts, a cartridge with a separate head, you don't mind losing the indicator. When no: photography, business documents or any HP with an integrated head. In those cases, a compatible is more cost-effective by the second print and without the risk of clogging the head, a recurring problem that Consumer Reports (2024) itself attributes to low-quality inks.

How do I prolong the useful life of my cartridges?

With storage and usage habits you can stretch each cartridge between 20% and 40%, above all by preventing the nozzles from drying out, which is the number-one cause of wasted ink. These are the seven that pay off most:

1. Print something in colour every 7-10 days. A test page is enough to keep the nozzles from drying.
2. Store upright, label up. It keeps the ink near the head and prevents bubbles.
3. Keep them between 15 °C and 30 °C. Away from radiators, sunny windows and cars; above 35 °C the ink degrades.
4. Don't open the blister until fitting. Air oxidises the pigments and dries out the internal sponge.
5. Clean heads once a month with the driver's utility; two cycles if you see light bands.
6. Turn off with the button, not by unplugging. The printer needs to park and seal the head.
7. Use suitable paper. An 80-90 g/m² paper absorbs less ink than a low-weight recycled one.

More tips by model in how to extend the life of your cartridges. And if you also see streaks, start by cleaning the print heads.

Does using compatibles void the warranty? The legal framework in the EU

It doesn't void it, and it's important to have that clear in writing. In the European Union, Directive (EU) 2019/771 on the sale of goods guarantees the consumer a minimum legal cover of two years that the seller cannot exclude, regardless of the consumable you use. In Spain it is transposed into Royal Legislative Decree 1/2007 (TRLGDCU).

The manufacturer can only deny the warranty if it proves that the failure was directly caused by the third-party cartridge. Simply installing a compatible is not a valid cause: the European Commission points out that the legal warranty is a right that cannot be excluded by a commercial clause (European Consumer Centres Network, 2024). In parallel, frameworks like WEEE (Directive 2012/19/EU) and REACH oblige the manufacturer itself to take on the end of life and chemical safety of the cartridge.

Your right, in plain terms. If an official service centre refuses to repair your printer "because you use compatibles", it is breaching the TRLGDCU and Directive 2019/771. Demand the answer in writing and, if it persists, complain to the Directorate-General for Consumer Affairs or the European Consumer Centre. The burden of proof lies with the manufacturer, not with you.

We develop it with case law in legal warranty on compatible cartridges in Spain.

Recycling and environmental footprint

Hundreds of millions of cartridges end up in landfill each year, and their plastic (ABS, PET, PP) takes centuries to break down. Recycling one has a measurable effect: according to the US EPA, reusing a cartridge's materials avoids extracting virgin oil and reduces emissions compared with making a new one. In Spain you have three legal, free routes:

• Municipal recycling point. Mandatory in municipalities of more than 5,000 inhabitants.
• Container at large stores. Media Markt, Carrefour, El Corte Inglés and Leroy Merlin have dedicated drop-off boxes.
• Manufacturer's postal service. HP Planet Partners, Canon Cartridge Recycling and Epson EcoReturns send a prepaid label.

Where and how, in detail, in where to recycle ink and toner cartridges.

Frequently asked questions

How do I identify the right cartridge for my printer?
Locate the exact model with the full suffix on the back label (for example, OfficeJet Pro 6970) and note the code printed on the installed cartridge (903XL, 304, PG-545). That code is your universal identifier, the same for original as for compatible. Search for it without spaces and in capitals, or ask us with the model in front of you.

Do compatibles have the same quality as originals?
For home and office use, the difference is imperceptible to the eye. The key is the manufacturer: Consumer Reports (2024) notes that the market is highly variable, so buy from whoever controls quality. On price, a reputable compatible works out between 40% and 75% cheaper per page than the OEM.

Does using compatibles void my printer's warranty?
No. Directive (EU) 2019/771 and art. 120 of the TRLGDCU protect you: the manufacturer can only deny the warranty if it proves the failure was directly caused by the third-party cartridge. Simple installation is not a cause. Ask for the answer in writing and complain to Consumer Affairs if they insist.

Is it worth refilling instead of buying compatibles?
Only in cartridges without an integrated head (Canon PGI/CLI, Epson 26/33) and for low demand. In HPs with an integrated head, the head degrades in two or three refills and quality drops. Refills also void the level chip. In the long run, a compatible is more cost-effective and reliable.

What's the difference between standard and XL?
The XL holds 2.5-3 times more ink in an almost identical casing, but costs only 60%-80% more, so the cost per page falls almost by half. Recommended if you print more than 40 pages a month; below 15, the standard prevents the ink from drying out before it's used.

Find your cartridge

Recognise the code, choose the capacity and buy from whoever controls quality. If you have the code to hand, look for your reference in the compatible ink cartridges collection or write to us with your printer's exact model and we'll tell you what fits.

Sources

1. ISO — ISO/IEC 24711:2021, method of measuring the yield of ink cartridges — https://www.iso.org/standard/77902.html
2. Consumer Reports — Third-Party Printer Ink Cartridges: Pros and Cons (2024) — https://www.consumerreports.org/printers/third-party-printer-ink-cartridges-pros-cons/
3. Official Journal of the EU (EUR-Lex) — Directive (EU) 2019/771 on the sale of goods — https://eur-lex.europa.eu/eli/dir/2019/771/oj/eng
4. European Consumer Centres Network (ECC-Net) — Guarantees and Warranties — https://www.eccnet.eu/consumer-rights/what-are-my-consumer-rights/shopping-rights/guarantees-and-warranties
5. Gizmochina — HP's Latest Firmware Update Blocks Third-Party Ink Again (2023) — https://www.gizmochina.com/2023/03/12/hp-blocks-third-party-ink-again/
6. abit.ee — HP Settles Third-Party Ink Lawsuit: Users Can Decline Blocking Firmware Updates (2024) — https://abit.ee/en/hard/printers/hp-dynamic-security-hp-third-party-ink-hp-cartridge-block-hp-firmware-settlement-hp-printer-lawsuit-en
7. US EPA — Frequent Questions on Recycling — https://www.epa.gov/recycle/frequent-questions-recycling