How to make and print barcode labels on a Mac

For your own stock, use Code 128. For products sold in shops, use the EAN or UPC number GS1 issued to you, never one you made up. Code 39 is for when an older system insists on it. Then print the barcode large enough, with a clear margin either side, at 100% scale, and scan a test label before you print the batch.

That is most of it. The rest of this guide is the reasoning, the free ways to do it on a Mac, and the printing details that decide whether the scanner beeps.

Code 128, Code 39 or EAN-13

These three cover nearly every small business label, and they are not interchangeable.

• Code 128 encodes letters, digits and punctuation, and it packs them densely, so a 10-character SKU fits on a small label. It is the default choice for anything internal: stock locations, SKUs, asset tags, order numbers. Shipping labels use it too.
• Code 39 is older and wider. It holds capital letters, digits, spaces and a handful of symbols (- . $ / + %), and the same data takes noticeably more width than in Code 128. Its advantage is that very old scanners and some legacy systems expect it. If nothing is asking for Code 39, you do not need it.
• EAN-13is the retail product barcode used across most of the world: 12 digits plus a check digit. It only means something if the number was issued to your company by GS1. Supermarket tills and marketplaces look the number up; a random 13 digits may belong to someone else's product.

Where UPC-A fits

In the US, retail products traditionally carry a 12-digit UPC-A. A UPC-A is the same number as an EAN-13 that starts with a zero, and the bars of that EAN-13 are identical to the UPC-A's; only the layout of the printed digits underneath differs. Scanners read both. If a retailer's artwork rules specifically require the UPC-A layout, though, you need a tool that draws UPC-A, and some of the tools below, including ours, do not.

Getting a real retail number

GS1 is the organization that issues these numbers, through a member organization in each country (GS1 US in the States). You license either a company prefix, which gives you a block of numbers, or single numbers if you only have a few products. Prices and options vary by country, so check your local GS1 site rather than a reseller of cheap numbers, whose codes may be registered to another company.

The free ways to make barcodes on a Mac

• Your printer's own software. DYMO Connect and Brother P-touch Editor both generate barcodes, free, for their own printers. If that is what you own, start there.
• Avery Design & Print Online. Free in the browser, generates barcodes and QR codes, and can fill them from a spreadsheet or number them in sequence. Best on Avery sheets.
• A barcode font in Pages or Word. Possible, but fiddly. A Code 39 font needs asterisks typed around the data, and a Code 128 font needs the text run through an encoder first to add start, stop and check characters. Typing a SKU in a Code 128 font does not produce a valid barcode.
• An online generator. Many will produce a barcode image to drop into any document. Prefer SVG or PDF output; if you only get a PNG, never scale it up or down in your document, because resampling softens the bar edges a scanner depends on.

Printing it so it scans

Most scanning failures come from printing, not from the design.

Leave the quiet zone empty

Every linear barcode needs blank space either side, called the quiet zone, so the scanner can find where the bars start. For Code 128 and Code 39 that is at least ten times the width of the narrowest bar. EAN-13 specifies 11 bar-widths on the left and 7 on the right. Text, a border or the edge of the label inside that space is one of the commonest reasons a barcode refuses to read.

Do not shrink it

An EAN-13 is designed to be about 37 × 26 mm, and GS1 allows it to go down to 80% of that. Below that, scanners struggle. Code 128 has no fixed size, but the same rule holds: the more characters, the wider it has to be for the bars to stay readable. If the barcode does not fit, shorten the data before you shrink the barcode. And print at 100%: a label fitted to a page is a barcode rescaled.

203 dpi versus 300 dpi

Most 4x6 thermal printers print at 203 dots per inch, which makes each dot about 0.125 mm. A bar can only be a whole number of dots wide, so the printer rounds every bar to the nearest dot. With a normal-sized barcode that rounding is harmless. With a long barcode squeezed into 40 mm, bars that should differ by a fraction of a dot come out the same width, and the barcode stops decoding. A 300 dpi printer, with dots of about 0.085 mm, has more room to get it right. On 203 dpi, give barcodes generous width.

Black, not gray

Too little heat leaves gray, soft-edged bars; too much spreads them into the gaps. Dithering turns solid bars into speckled ones. If your test label fails, work through why barcodes won't scan after printing and faded thermal labels before changing the design.

Making barcode labels in LabelPrint

The free options above are fine when they match your printer. If you print on a generic thermal roll, or the barcode needs to change from label to label, the designer in LabelPrint does it this way:

1. Start from a blank label at your roll's size, or a template such as the asset tag, inventory tag or price tag.
2. Add a barcode, choose Code 128, Code 39 or EAN-13, and type the value. Turn on the caption if you want the value printed as text under the bars.
3. For EAN-13, type the 12 digits and the app adds the check digit, or type all 13 and it tells you if the last one is wrong. For Code 39 it flags characters the format cannot hold. Code 128 is limited to plain ASCII, so accented letters are spelled without accents.
4. Print a single label and scan it with the scanner you will actually use, before printing the rest.

Two things make it useful past a single barcode. A barcode's value can include {{serial}}, so a series of asset tags each gets its own number in both the text and the bars (see numbered labels). And a barcode can be filled from a column of a spreadsheet, one label per row (see printing labels from a CSV).

What it does not make: UPC-A, DataMatrix, PDF417 or GS1-128. If your retailer or warehouse requires one of those, use software that supports it. And printing any label with a barcode on it needs Unlimited; designing one is free, which at least lets you check it will fit before deciding. Pricing is here.