Generatore di codici a barre

Barcodes look alike, but each symbology has its own rules about which characters it accepts, how long the value must be and how the check digit is calculated. A label printed with the wrong type or a bad check digit simply will not scan. This generator knows the rules for six widely used types and tells you in plain language when a value does not fit.

Type a value and the barcode is drawn instantly in your browser. For the numeric retail and carton formats, enter the number without its last digit and the check digit is added, or enter the full number and it is verified. Download the result as a PNG image or as an SVG that prints with perfectly crisp bar edges at any size.

Barcode types and what they are for

Code 128 is the general-purpose choice: it encodes letters, digits and common symbols compactly and is used on shipping labels, asset tags and internal inventory. Its mandatory modulo-103 check character is calculated by the encoder and does not appear in the text under the bars. Code 39 is older and wider but still required in some automotive, defence and healthcare systems; it accepts digits, capital letters and the symbols - . space $ / + %, and the generator converts lowercase letters to capitals for you.

EAN-13, UPC-A and EAN-8 are the retail symbols scanned at checkouts. EAN-13 holds 13 digits and is used worldwide, UPC-A holds 12 digits and dominates in the United States and Canada, and EAN-8 is a short form for small packs. ITF-14, based on Interleaved 2 of 5, holds a 14-digit trade item number and is printed on outer cartons and cases, where its thick bars survive corrugated cardboard. All four end in a GS1 check digit.

Typical uses

How the GS1 check digit is calculated

EAN-13, EAN-8, UPC-A and ITF-14 all use the same modulo-10 rule. Starting from the rightmost digit of the number without its check digit, multiply the digits alternately by 3 and 1, add the results, and take the amount needed to reach the next multiple of 10 (0 if the sum already is one). For 400638133393, the weighted sum is 89, so the check digit is 1 and the full EAN-13 is 4006381333931. The rule catches every single-digit typo and most swaps of neighbouring digits.

When you type 12 digits for EAN-13, 7 for EAN-8, 11 for UPC-A or 13 for ITF-14, the tool appends the check digit and shows the completed number. When you type the full length, it verifies the last digit and, if it is wrong, tells you the correct code. The barcode is then drawn as vector graphics with black bars on white. Bar width sets the width of the narrowest bar, from 1 to 4 pixels; Height runs from 40 to 200 pixels; the PNG download is rendered at twice the on-screen size.

Come usare questo strumento

1. 1Choose a Barcode type from the list. If the current value does not suit the new type, an example value is filled in.
2. 2Type your value. For numeric types, leave off the last digit to have the check digit added, or enter the full number to verify it.
3. 3Adjust Bar width and Height, and decide whether to show the value under the bars.
4. 4Download the barcode as PNG or SVG.
5. 5Print a test label and scan it with the scanner or phone app that will be used in practice.

Limitations

• This tool draws barcodes; it cannot issue numbers. EAN and UPC codes for products sold in shops must come from a GS1 company prefix licensed to your business.
• GS1-128 with application identifiers, 2D symbols such as Data Matrix or PDF417, and add-on codes for books and magazines are not supported. For a 2D code, use the QR code generator.
• Code 128 accepts printable ASCII characters only, so accented letters and non-Latin scripts are rejected. Code 39 is drawn without its optional modulo-43 check character.
• Bars are always black on white with a fixed white border, and there are no colour or bearer-bar settings.