How to Make a Barcode for a Product: A Step by Step Guide From SKU to Shelf

To make a barcode for a product, decide first where the product will sell: only inside your own business, or through outside retailers. Internal products can carry a free Code 128 barcode generated from your SKU text in minutes, while retail products need a number assigned through GS1, then rendered as a UPC-A or EAN-13 symbol.

That single fork decides your cost (zero versus license fees), your timeline (minutes versus days), and which tools you use. This guide walks the whole path in the order you should actually do it: the fork, the internal route, the retail route, SKU design, label printing, and testing before you commit to a 500 label run.

Internal only or retail: the fork that decides everything

Ask one question: will any business other than yours ever scan this barcode at a checkout? Your answer sorts you into one of two paths.

• Internal only: your own point of sale, warehouse bins, stock counts, repair or rental tracking. You invent the numbers yourself, the format is Code 128, and the cost is zero.
• Retail: grocery and big box chains, pharmacies, Amazon, and most large marketplaces. The number must be a GTIN licensed to you through GS1, printed as UPC-A (12 digits, US and Canada) or EAN-13 (13 digits, most of the rest of the world).

If you are unsure, start internal. A Code 128 label takes minutes, and nothing about it blocks you from adding a GS1 number later. Plenty of small brands run both at once: Code 128 on stockroom bins, UPC-A on the retail packaging.

The internal path: Code 128, free, working the same day

Code 128 encodes the full 128 character ASCII set, so letters, digits, and hyphens all work, and it is the densest of the common linear formats for alphanumeric data. That is why it is the default for internal SKUs. The process has three steps.

• Write your full SKU list in a spreadsheet. This file is your master record from now on.
• Paste each SKU into the free barcode generator, pick Code 128, and download the PNG or SVG.
• Print, stick, scan.

Any USB barcode scanner behaves as a keyboard: plug it in, pull the trigger, and the SKU types itself into whatever field your cursor sits in. No drivers, no software, and entry level scanners in the 30 to 80 dollar range read Code 128 out of the box. Sellers with style, color, and size variants can use the garment barcode generator, which is built around exactly that SKU pattern. Barcoding a catalog of a few hundred products is a one afternoon job.

The retail path: GS1 number first, barcode second

A retail scanner does not read your product name from the bars. It reads a 12 or 13 digit number and looks it up in the store's catalog. If that number was never assigned to you, the lookup fails or, worse, collides with someone else's product. That is why retail numbers come from GS1, the nonprofit that licenses company prefixes worldwide, and not from a generator.

• Company prefix: the initial license fee scales with how many numbers you need. Small capacities start in the low hundreds of dollars, large capacities run into the thousands, and an annual renewal fee applies on top. One prefix covers your whole product line.
• Single GTINs: GS1 US also sells one-off numbers for roughly 30 dollars each with no renewal. Below about 10 products, this is usually the cheaper route.
• Timeline: numbers are assigned quickly once payment clears, typically the same day to a few days.

Once GS1 assigns your numbers, turn them into symbols: the UPC barcode generator for the 12 digit US and Canada format, or the EAN-13 barcode generator for the rest of the world. Both calculate the final check digit for you. One warning: skip third party resellers offering cheap recycled prefixes. Marketplaces increasingly verify GTIN ownership directly against the GS1 database, and a code still registered to a defunct company from the 1990s fails that check.

Design the SKU scheme before you generate anything

Generating barcodes takes minutes. Renaming 300 products after your first scheme collapses takes weeks, so design the scheme first. The pattern that scales is segment based: a category or style code, then attributes, separated by hyphens.

• MUG-CER-BLU-11OZ: ceramic mug, blue, 11 ounce
• CANDLE-SOY-VAN-8OZ: soy candle, vanilla, 8 ounce
• SOAP-LAV-100G-2603: lavender soap, 100 gram, batch from March 2026

Three rules keep it sane. Keep each segment 3 to 8 characters. Fix your abbreviations once, so BLK always means black. Never reuse a retired code, even years later, because old labels outlive old products. The payoff shows at scale: a line with 12 base products, 4 variants, and 6 sizes needs 288 unique codes, and a fixed scheme lets you build that list with spreadsheet fill down in minutes instead of inventing 288 names by hand.

Label printing: sizes and printers that actually scan

Retail formats have fixed dimensions set by the GS1 specifications, while internal Code 128 sizing is up to you. The numbers that matter:

The quiet zone is blank space measured in multiples of the narrowest bar, and crowding it is the single most common reason a printed barcode refuses to scan. On corrugate cartons, keep ITF-14 near the top of its size range, because rough board spreads ink and blurs narrow bars. On printers, the choice is mostly volume and durability. Direct thermal needs no ink but the print fades in months, faster in heat and sunlight, so it suits shipping labels, not product labels. Thermal transfer uses a ribbon, survives years of handling, and is the product label standard: a 203 dpi head lays dots of about 0.125 mm, so bar widths should land on whole multiples of that, while 300 dpi gives cleaner edges on small labels. Laser on sheet labels works fine at low volume, but toner spread can choke bars, so stay at 90 percent magnification or above on plain paper stock.

If the same label also needs a scannable link, care instructions, or a reorder page, print a QR code next to the barcode. The QR code for labels tool covers sizing, materials, and contrast for that side of the job.

Test before you print in volume

Every failed barcode in the field costs a manual lookup, roughly 10 to 20 seconds each, hundreds of times. Ten minutes of testing removes that tax.

• Print one strip or sheet on the exact printer, stock, and size you plan to use, never a draft on plain paper.
• Scan with your cheapest scanner and a phone camera. If the worst device reads it, the whole fleet will.
• Scan the first and the last label of the run. Thermal printheads drift as they heat up.
• Check the human readable digits under the bars against your spreadsheet. A typo in the source data prints perfectly and scans perfectly, straight into the wrong product.
• If a retail partner requires graded verification, linear barcodes are measured under ISO/IEC 15416 (2D codes like QR fall under ISO/IEC 15415), and GS1 requires a minimum grade of 1.5, the low end of a C, for most symbols.

Barcoding a product line is a sequence, not a single tool: pick the path, get the numbers, fix the SKU scheme, print, test, then scale. Every generator mentioned here is free and runs in the browser, and our guides library has deeper dives into printing, scanning, and label formats when you hit the next question.

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