Barcode Generator

This barcode generator turns a product number or a piece of text into a scannable linear barcode and lets you download it as a PNG or SVG. It is for small sellers labelling stock, warehouses printing shelf and carton labels, and anyone who needs a barcode image for a document or a mock-up — free, with no sign-up and no watermark.

Six symbologies are built in. EAN-13 and UPC-A are the retail barcodes on consumer products (UPC-A is the 12-digit form used in the US and Canada); EAN-8 is the short version for small packs; ITF-14 goes on outer shipping cartons; Code 128 encodes any plain-ASCII text compactly; Code 39 encodes capital letters, digits and a few symbols and is still common on industrial and ID labels. For the retail and carton types you can type the number without its last digit and the GS1 check digit is calculated for you, or type all of it and the tool tells you if the check digit is wrong — and what it should be.

The encoders are written from the published tables, not copied from a library. EAN, UPC and ITF-14 follow the GS1 General Specifications (Release 26.0): the left-half parity patterns, the guard bars that extend 5 modules below the others, and the minimum quiet zones (11 and 7 modules either side of an EAN-13, 9 for UPC-A, 7 for EAN-8, 10 for ITF-14). Code 128 follows ISO/IEC 15417 and picks code sets A, B and C automatically to make the shortest possible barcode, with the mod 103 check character. Reference patterns for every symbology are pinned in automated tests and match an independent encoder, and the downloaded PNGs were decoded back with the open-source zxing-cpp reader during testing.

Sharpness is designed in. Each bar is a whole number of pixels wide (you choose 1 to 10 pixels per module), and wide elements in Code 39 and ITF-14 are exactly 3 modules, so every bar edge in the PNG falls exactly on a pixel boundary: the bars have no grey, blurred edges for a scanner to misread (only the optional digits underneath are anti-aliased, like any text). For print, download the SVG: it is vector, so you can set the exact physical size in your layout software. At GS1's nominal size an EAN-13 is 37.29 mm wide including quiet zones with 22.85 mm bars (a 0.330 mm module).

One thing a generator cannot do is give you a valid product number. Retail EAN and UPC numbers are GTINs issued under a GS1 Company Prefix licensed from a GS1 Member Organisation; the barcode is only a picture of that number. Make up a number and the barcode will scan, but it will not identify your product in retailers' systems.

Everything runs in your browser: the number you type and the image you download never leave your device. You can confirm in your browser's developer tools (Network tab) that no request carries your data.

1. Your input is validated for the chosen symbology. Spaces and hyphens in product numbers are ignored; anything the symbology cannot encode is named in the error message. 2. For EAN-13, UPC-A, EAN-8 and ITF-14 the GS1 check digit is computed: multiply the digits by 3 and 1 alternately, starting with 3 at the rightmost digit, add them up, and take the amount needed to reach the next multiple of 10. If you typed the check digit, it is compared with this value. 3. Each character is converted to its bar pattern from the published tables — GS1 number sets A, B and C with the leading digit's parity pattern for EAN-13; GS1 wide/narrow patterns for ITF-14, interleaving bars and spaces in digit pairs; the 43-character Code 39 table with * start/stop and an optional mod 43 check character; and the 107-pattern Code 128 table. 4. For Code 128, a shortest-path search chooses where to use code set A (control characters), B (lowercase and symbols) or C (pairs of digits), adding SHIFT or code-change characters only where they make the barcode shorter. The check character is (start value + each value × its position) mod 103. 5. The modules are laid out as an SVG: quiet zones, bars at whole-pixel positions, guard bars extended 5 modules for EAN/UPC, bearer bars (4 modules thick) for ITF-14, and the human-readable text in a monospace font. 6. Download PNG draws that SVG onto a canvas at exactly its pixel size and saves it losslessly; Download SVG saves the vector file as it is.