Disclosure: Clever Supplies sells compatible printer cartridges — which is exactly why we'd rather you buy the right number the first time than the wrong one twice.

You don't need the manual, and you don't need to call anyone. The cartridge number is printed on the printer itself — or one menu away. Here are three methods, fastest first. Total time: about a minute.

Why bother getting it exactly right? Because a wrong cartridge is a special kind of annoying: it doesn't fit, or it fits but the printer rejects it, and now you're repackaging a return instead of printing. Sixty seconds here saves you the whole dance.

Method 1: Open the front door (30 seconds)

The cartridge number is printed on the cartridge itself, and usually also on a label inside the compartment. Open the same door or flap you'd open to change the cartridge, and look.

Where to look, by brand:

• HP LaserJet: Open the front pull-down door. The toner cartridge faces you, and there's usually an inner label listing the cartridge (e.g., "CF258A").
• HP inkjet (DeskJet, OfficeJet, Envy): Lift the scanner lid or open the ink access door. The cartridges sit in a sliding carriage; the number is printed on each cartridge's label.
• Brother laser: Drop the front cover. The toner cartridge slides toward you — on most current models you'll see something like "TN830" or "TN920" printed on the cartridge, often with an inner label listing it too. Color models (like the HL-L32xx series) have four slots: black plus cyan, magenta, and yellow, each with its own number (e.g., TN229 series).
• Canon imageCLASS (laser): Open the front cover. The toner cartridge is inside, and a rating label inside the cover typically lists the consumables.
• Canon PIXMA (inkjet): Open the top cover. The print-head holder slides to the center; each ink tank has its number printed on top (e.g., PG-245).
• Epson: Lift the scanner unit or open the ink cover. Cartridges — or the EcoTank fill bay — carry the numbers (e.g., 522, T502). On EcoTanks, the bottle numbers are printed right by each tank.
• Lexmark: Open the front door. The toner cartridge is right there, with its number on the cartridge and usually on the inner door label.

Pro tip: take a phone photo of the label. Future-you will be grateful.

Method 2: Ask the printer — without getting up

A. The control panel. Look for a menu called Setup or Settings, then an item like Reports, Tools, or Information. You're hunting for anything named Configuration Report, Supplies Status, or Print Quality Report — one of these lists the installed cartridge numbers. (Exact names vary by model; don't memorize a button sequence, just look for the "Reports" family.)

B. From your computer. This works even if the printer is in another room:

• Windows 11: Settings → Bluetooth & devices → Printers & scanners → click your printer. Many drivers show an Estimated Levels or Supplies tab right there with cartridge numbers. (Windows 10: Settings → Devices → Printers & scanners — same idea.)
• macOS: System Settings → Printers & Scanners → select your printer → Options & Supplies → Supply Levels. Most models show cartridge type and levels here.
• Brand apps: HP Smart, Brother iPrint&Scan, Canon PRINT, and Epson Smart Panel all have a supplies/levels screen that names the cartridges.

C. The manufacturer's lookup page. If all else fails, every major brand has a "find supplies for my printer" page: type in your printer model number and it tells you the cartridge numbers. Slowest method, but foolproof.

Reading the number right

Cartridge codes look cryptic, but there's a logic to them:

• The trailing letters usually mean page yield. Take Brother's TN920 family: TN920 is the standard cartridge, TN920XL is high yield, TN920XXL is extra-high yield, and TN920UXXL is the ultra-high-yield version — same physical fit, each step just prints more pages. Same story with Brother TN229 vs TN229XL vs TN229XXL, TN635 vs TN635XL vs TN635XXL, and HP 58A vs 58X.
• Match the full code, letters included. "TN920" alone isn't specific enough — TN920 and TN920XXL are different products at different prices. The suffix is part of the product.
• Similar numbers can mean totally different cartridges. Brother TN730 and TN760 look alike but fit different printer series. TN820, TN850, and TN880 are a tiered family for the same machines — don't guess from memory, read the label.

The five most common mix-ups:

• Toner vs. drum (Brother lasers). TN = toner, DR = drum. They're different parts with different replacement cycles — if your prints are faded, you need toner (e.g., TN830); if they're streaky after a fresh toner, it's probably the drum (e.g., DR830). Common pairs: TN730/DR730, TN830/DR830, TN920/DR920.

• Printer model ≠ cartridge number. "HL-L2390DW" is the printer. "TN830" is the cartridge. Searching the printer model when you mean the cartridge is the #1 cause of wrong orders.

• "SETUP" cartridges. The cartridges that ship in the box often say something like "SETUP TN830." That's a starter cartridge — when you buy replacements, drop the SETUP prefix and buy the regular TN830.

• Black vs. color numbers. On color lasers, black has its own number (e.g., Brother TN229 black) and each color has its own (TN229 cyan, magenta, yellow — also in XL and XXL versions). A "4-pack" listing bundles them; the individual numbers still matter.

• Regional letters. Some cartridges have region-specific suffixes. When in doubt, match exactly what's printed on your current cartridge.

What to do with the number once you have it

Search the full cartridge number together with your printer model. Any reputable compatible listing will state which OEM number it replaces — match that statement against the number on your cartridge, letter suffix and all. That's the whole trick; there's nothing else to decode.

FAQ

My printer shows two numbers — which one do I need?

Probably toner + drum (common on Brother lasers — e.g., TN830 toner and DR830 drum) or a black + color set. They're separate parts — replace only what's actually empty. If you're unsure which is empty, the supplies report from Method 2 tells you levels per part.

Is the number on the printer's box enough?

No. The box shows the printer model, not the cartridge. You need the cartridge number from inside the printer, its menu, or the manufacturer's lookup page.

The label inside wore off. Now what?

Print a configuration or supplies report from the printer's menu (Method 2A), check the supplies tab on your computer (Method 2B), or use the manufacturer's supplies lookup with your printer's model number (Method 2C). One of the three always works.

Does the trailing letter really matter — TN920 vs. TN920XXL?

Yes. Same fit, different page yield. XL, XXL, and UXXL (depending on the family) mean higher yield: more pages per cartridge, higher upfront price, lower cost per page. Buy the version that matches how much you print.

I found a number starting with "SETUP" — is that the cartridge number?

Almost. That's the starter cartridge that came in the box. The retail version is the same number without the SETUP prefix — so "SETUP TN830" means you buy TN830.

Quick-reference cheat sheet

Brand	Fastest spot	If the label's gone
HP LaserJet	Inside the front door	Setup → Reports → Configuration Page
HP inkjet	Ink carriage under the lid	HP Smart app → Supplies
Brother	Behind the drop-down front cover	Machine Info / Reports menu
Canon laser	Inside the front cover	Settings → Output Report
Canon inkjet	Ink tanks under the top cover	Canon PRINT app → Ink levels
Epson	Ink bay / EcoTank fill bay	Epson Smart Panel / Status Monitor
Lexmark	Inside the front door	Menus → Reports → Menu Settings Page

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