Barcode Generator

Make retail, shipping and book barcodes from one number, sized for print

A barcode is a number drawn as bars and spaces of different widths. This generator draws the bars as soon as you enter a number, and for numeric types it works out and appends the final check digit. Choose EAN-13 and enter the product number 541234567890: the check digit 8 is added to give 5412345678908, and at the defaults (300 dpi, scale closest to 100%, which is 102.6%) the label comes out 38.27 mm wide including its quiet zones.

The structure strip under the label splits the barcode into sections from the left quiet zone to the right one. Point at a cell and the label marks which bars draw that digit, while the check calculation spells out how each check digit was reached.

When you need to make a barcode yourself

A barcode image is needed in more situations than you might expect, and each one calls for a different type and a different first check.

• Packaging for a new product: enter the number your GS1 member organization gave you as EAN-13 (or UPC-A for US retail) and hand the printer an SVG or PDF. This tool does not issue the number.
• Cartons for a warehouse: print a GTIN-14, the single-item number with a packaging level digit in front, as ITF-14. The check digit has to be recalculated whenever the first digit changes.
• Inventory, location and shipping labels: make internal letter-and-digit codes as CODE128, and use the many-at-once mode to get a print sheet in one go.
• Self-published books: make the 13-digit ISBN as EAN-13 and put the 5-digit add-on in the add-on field when you need one.
• Images for web pages and documents: choose 96 dpi and the PNG has bar widths that land exactly on screen pixels.

How to use it

1. Pick a barcode type from the samples at the top. Each sample is a small real barcode with its main use.
2. Enter the number or content. For numeric types, leave the check digit off and it is added; if you paste a full number it is checked. Spaces, hyphens and full-width digits are cleaned up for you.
3. The scale under the label is in real millimeters. Set the scale (or bar width) and bar height, then choose the resolution of the printer you will use.
4. Save as PNG, SVG or PDF, or copy the image. For several numbers, switch to Many, enter one per line, and download a print-sheet PDF or a ZIP.
5. Scan the printed barcode once with the scanner or phone app that will actually be used.

Eight barcode types and where each is used

For a new internal numbering scheme, CODE128 holds the same content in the least space, because set C packs two digits into one symbol wherever digits run together. INV-20261023-0042, for example, becomes 17 symbols in this tool, counting start, check and stop.

Product barcode numbers are issued separately

Drawing a barcode and getting a product number are two different things. The 13-digit number on a retail product (GTIN-13) begins with a company prefix licensed by a GS1 member organization, one for each country or region. In the United States that organization is GS1 US, which describes a GS1 Company Prefix as a number unique to each member that identifies you as the owner of the brand. An EAN-13 you invent can collide with a number another company already owns.

• The first digits are not the country of origin: GS1 says its prefixes do not identify the country of origin. They show which GS1 member organization issued the number (the list gives 001 to 019, 030 to 039 and 060 to 139 to GS1 US, for example), not where the product was made.
• Books use an ISBN: prefixes 978 and 979 belong to the International ISBN Agency. It states that if you only want the ISBN in bar-coded form, you do not have to become a member of GS1. Ask your national ISBN agency how to get one.
• Internal numbers: stock and asset numbers used only inside your business do not need a GS1 number. Choose them freely with CODE128 or CODE39.

Working out the check digit: 541234567890 is followed by 8

The last digit of an EAN, UPC or ITF-14 number is a check digit, which catches a digit that was misread or mistyped. Take the number without its check digit, multiply the digits by 3, 1, 3, 1... alternating from the right end, add everything up, and subtract the total from the next multiple of 10.

5×1 + 4×3 + 1×1 + 2×3 + 3×1 + 4×3 + 5×1 + 6×3 + 7×1 + 8×3 + 9×1 + 0×3 = 102 → 110 − 102 = 8

The ITF-14 row takes the single-item number 5412345678908, drops its check digit 8 and puts packaging level 1 in front. Counting from the right, every original digit keeps its weight, and the new 1 is multiplied by 3, so the sum rises from 102 to 105. The check digit therefore changes from 8 to 5. The ISBN in this row is a sample number.

The first digit of an EAN-13 has no bars of its own. Instead, the left six digits are drawn from two patterns, L (odd) and G (even), and the order in which they are used stands for the first digit. For 5412345678908 the first digit is 5, so the left six digits are drawn in the order L G G L L G and the right six all in R. The check calculation under the barcode shows this order too.

Print size: scale, bar width, height and quiet zones

Barcode size is set by X, the width of the narrowest bar. For EAN and UPC, X of 0.330 mm counts as 100%. At that size an EAN-13 is 37.29 mm wide including quiet zones, with bars 22.85 mm high. When you resize, change width and height by the same proportion.

The EAN and UPC ranges in this table are for products scanned only at the retail checkout (GS1 symbol specification table 1). Products whose barcode is also scanned in general distribution (table 3) use X of at least 0.495 mm (target 0.660 mm, scale 150 to 200%), and an EAN-13 bar height of at least 34.28 mm at that minimum X.

A printer can only place whole dots, so bar width ends up a whole number of dots. This table shows how an EAN-13 at 100% lands at each resolution.

On a 203 dpi label printer, 2 dots (0.250 mm) is thinner than the 0.264 mm minimum, so 3 dots is the smallest size inside the standard. Stretching or shrinking a saved PNG in a document program breaks this fit. Place the PNG at its own size, or use the SVG or PDF, which scale cleanly. The PNG records the dpi you chose, so programs that read dpi open it at its real size in millimeters.

Before you print

• Quiet zones: the blank space on both sides is part of the barcode. Keep text, lines and borders out of the hatched cells in the structure strip.
• Color: GS1 measures print quality with red light at a wavelength of 660 nm (quality spec 1.5/06/660). Under red light, red, orange and yellow bars look as bright as the background, so use dark bars such as black, dark blue or dark green on white or a light color. The red-light contrast reading beside the tool puts a number on this.
• Height: if you shorten only the height of an EAN or UPC for checkout use, scanners struggle to read it at an angle. When space is short, reduce the whole scale instead.
• Digits: GS1 requires the digits in an EAN or UPC to be printed as human-readable text as well. Turn the digits off only for internal labels.
• ITF-14 bearer bars: ITF-14 calls for bearer bars, top and bottom or all round. If you print directly on corrugated board with plates, use X of at least 0.635 mm and a full frame (4.83 mm).
• A real scan: print quality, ink spread and label material all change the result. Scan a few copies with the real scanner before a large run.

Common mistakes

• Leading zeros vanish in a spreadsheet: a number like 0614141... loses its 0 in a number cell. Set the cells to text before pasting into Many mode.
• You added the check digit yourself and it is one digit off: if a 13-digit entry gives an error, one of the first 12 digits probably differs from the original. Use the fix-last-digit button only when you are sure the original is right.
• A 13-digit number entered for ITF-14: the tool treats 13 digits as the single-item number and puts the packaging level in front. If you already have a 14-digit trade item number, enter all 14.
• A 10-digit ISBN: the old 10-digit ISBN cannot be made into a barcode. Put 978 in front to get 13 digits, and the check digit is calculated again.
• Lowercase in CODE39: the basic CODE39 set has no lowercase, so letters become capitals. Use CODE128 if lowercase has to be kept.
• Using a screenshot: a screen capture smears bar widths to fit screen pixels. Use the file from the save buttons.

Limits

• This tool draws barcodes. It does not issue GTINs or ISBNs, and it cannot check whether a number is registered.
• It does not make 2D codes such as QR or Data Matrix, GS1-128 application identifiers (AI) and FNC1, GS1 DataBar, or postal barcodes. For QR codes, use a QR code generator.
• CODE128 accepts only the 95 printable ASCII characters. Control characters, extended characters (FNC4) and other scripts cannot be entered.
• The human-readable digits are drawn in a Helvetica or Arial style font. GS1 recommends OCR-B, but it also allows another font that is easy to read.
• The print sheet is a fixed layout with 10 mm margins and 4 mm between cells. To match the cells of commercial label stock exactly, use a label printer or label software.
• Red-light contrast is an estimate computed from screen color values. Real read rates depend on ink, paper and printing method.

Basis: sizes, quiet zones, heights, add-on barcodes and ITF-14 rules follow GS1 General Specifications Release 26.0 (January 2026); prefixes and country of origin follow the GS1 prefix list, and company prefixes follow GS1 US. The International ISBN Agency page on ISBN bar coding was read on October 23, 2026. Bar patterns were compared against JsBarcode 3.12.1, and saved images were read back with an OpenCV decoder.

Sources

• 1GS1 General Specifications, Release 26.05.2 EAN/UPC (X 0.264 to 0.660 mm, 100% width 37.29 mm and height 22.85 mm, quiet zone table 5-11, add-on barcodes), 5.3 ITF-14, 5.4 GS1-128, table 5-44
• 2GS1 US: What Is a GS1 Company Prefix?A company prefix is unique to each member and identifies the brand owner
• 3GS1 US: How to Get a UPC BarcodeLicensing a company prefix as a GS1 US member
• 4GS1: GS1 Company Prefix (archived copy)Prefixes do not identify the country of origin; prefix ranges by member organization
• 5International ISBN Agency: ISBN Bar CodingNo GS1 membership is needed to use the ISBN in bar-coded form

Frequently asked questions

Tools to use with it