How to Generate a Barcode
A barcode is a number written in a pattern of bars and spaces that a scanner can read reliably at speed and at an angle. Which format you need depends entirely on where it is going — a retail till, a warehouse shelf, a shipping carton. Pick the right one, enter your value, and the check digit is calculated for you.
Pick the format
EAN-13 for retail worldwide, UPC-A for North America, Code 128 for anything internal.
Enter your value
Type the digits you have. The final check digit is worked out and appended automatically.
Download SVG or PNG
SVG for printing at any size, PNG when a system will only accept a raster image.
The Check Digit Is the Whole Game
EAN, UPC and ITF codes all end with a check digit, and it is not decorative. The scanner recalculates it from the other digits and compares. If they disagree, the read is rejected outright — which is exactly what you want, because a misread product code is worse than no read at all.
The arithmetic is a modulo-10 calculation: working from the right, digits are multiplied alternately by three and one, summed, and the check digit is whatever brings that total up to the next multiple of ten. It is simple enough to do by hand and, for reasons that are hard to explain, it is the thing a surprising number of online generators get wrong. A barcode with a bad check digit looks completely normal on screen and fails silently at the till.
This tool calculates it for every format that needs one and shows you the result before you download, so you can check it against whatever your supplier or GS1 registration gave you. Type only the digits you were issued— twelve for EAN-13, eleven for UPC-A — and let the last one be computed.
Choosing the Right Format
EAN-13 for retail, almost anywhere
The global standard for products sold in shops. The number itself must be issued through GS1 - you cannot invent one and expect it to be unique.
UPC-A for North America
Twelve digits, structurally identical to EAN-13 with a leading zero. North American systems expect this form.
Code 128 for anything internal
Encodes letters, digits and punctuation at any length, and packs densely. The right choice for asset tags, internal references and warehouse labels.
ITF-14 for shipping cartons
Encodes the case-level code on outer packaging. Its thick bars survive printing directly onto corrugated cardboard, where finer codes fail.
Frequently Asked Questions
How do I generate a barcode for free?
Choose a format, enter your value, and download as SVG or PNG. Free, no signup, and no watermark.
Does it calculate the check digit?
Yes, for every format that needs one. Enter only the digits you were issued and the final one is computed and shown.
What is a check digit and why does it matter?
A digit derived from the others that the scanner recalculates and verifies. Get it wrong and the barcode looks fine but will not scan.
Which barcode format should I use?
EAN-13 for retail worldwide, UPC-A for North America, Code 128 for internal use, ITF-14 for shipping cartons.
Can I invent my own EAN-13 number?
For testing yes, but not for real products. Retail numbers must be issued through GS1 to guarantee they are globally unique.
Should I download SVG or PNG?
SVG for anything printed - it stays sharp at any size. Barcodes scaled up from a small PNG frequently fail to scan.
Why will my printed barcode not scan?
Usually printing too small, or scaling a raster image. Keep the quiet margin either side, print at full size from vector, and use strong contrast.
Does Code 128 accept letters?
Yes, the full printable ASCII range, at any length. That flexibility is why it dominates internal and logistics use.
Is my product code uploaded anywhere?
No. The barcode is generated entirely in your browser.
Can I change the colours?
Yes, though be careful. Scanners need strong contrast, and red bars in particular are invisible to many red-light laser scanners.
What is the number printed underneath?
The human-readable form, so the code can be typed manually if a scan fails. Keeping it is standard practice for retail.
Is this barcode generator really free?
Completely free, with no limits, no watermark, no signup and no premium wall.
Last updated: July 21, 2026 · FlipMyFormat Barcode Generator
Written and maintained by the FlipMyFormat team