{"id":117,"date":"2026-05-04T19:47:43","date_gmt":"2026-05-04T23:47:43","guid":{"rendered":"https:\/\/simpletool.io\/blog\/?p=117"},"modified":"2026-05-04T19:47:43","modified_gmt":"2026-05-04T23:47:43","slug":"barcode-generator","status":"publish","type":"post","link":"https:\/\/simpletool.io\/blog\/barcode-generator\/","title":{"rendered":"Barcode Generator: Code 128, EAN-13, UPC, ITF [2026]"},"content":{"rendered":"
TL;DR:<\/strong> A barcode generator turns a string of digits or alphanumeric characters into a scannable bar pattern in a chosen symbology (Code 128, EAN-13, UPC-A, Code 39, ITF, MSI). The right symbology depends on what you’re encoding: EAN-13<\/strong> for retail products in Europe and most of the world, UPC-A<\/strong> for North American retail, Code 128<\/strong> for shipping labels and inventory, ITF-14<\/strong> for outer cartons. Our free barcode generator<\/a> renders all of these in your browser as PNG or SVG.<\/div>\n

Barcodes look interchangeable from a distance but they’re a small zoo of incompatible standards. Use UPC-A on a European retail product and the supermarket scanner will reject it; use Code 39 on a shipping label and your carrier’s reader may not parse it. Picking the right symbology matters more than the visual styling. Once you’ve picked, generation is mechanical: encode your data, draw the bars, optionally add the human-readable digits underneath, export.<\/p>\n

Our barcode generator<\/a> supports 8 symbologies covering 95% of real use cases \u2014 Code 128 (the modern default), EAN-13 \/ EAN-8 (retail global), UPC-A \/ UPC-E (retail North America), ITF-14 (outer cartons), Code 39 (legacy alphanumeric), and MSI (warehouse shelving). Outputs are scalable SVG (for print) or PNG (for screens). This guide covers which symbology to pick, the data formatting rules per type, and the print-quality details that make the difference between a barcode that scans every time and one that fails 5% of the time.<\/p>\n

Which barcode symbology should you pick?<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n
Symbology<\/th>\nBest for<\/th>\nData type<\/th>\nLength<\/th>\n<\/tr>\n<\/thead>\n
EAN-13<\/strong><\/td>\nRetail products globally<\/td>\nDigits 0-9<\/td>\n12 + 1 check digit<\/td>\n<\/tr>\n
UPC-A<\/strong><\/td>\nRetail in North America<\/td>\nDigits 0-9<\/td>\n11 + 1 check digit<\/td>\n<\/tr>\n
Code 128<\/strong><\/td>\nInventory, shipping, internal IDs<\/td>\nAll ASCII<\/td>\nVariable (1\u201380 typical)<\/td>\n<\/tr>\n
ITF-14<\/strong><\/td>\nOuter shipping cartons<\/td>\nDigits, even count only<\/td>\n14 fixed<\/td>\n<\/tr>\n
Code 39<\/strong><\/td>\nGovernment, legacy systems<\/td>\nA-Z, 0-9, -.$\/+%<\/code><\/td>\nVariable<\/td>\n<\/tr>\n
EAN-8<\/strong><\/td>\nSmall retail items (where EAN-13 won’t fit)<\/td>\nDigits 0-9<\/td>\n7 + 1 check<\/td>\n<\/tr>\n
UPC-E<\/strong><\/td>\nCompressed UPC for small packaging<\/td>\nDigits 0-9<\/td>\n6 + 1 check<\/td>\n<\/tr>\n
MSI<\/strong><\/td>\nWarehouse shelving<\/td>\nDigits 0-9<\/td>\nVariable<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

If unsure: pick Code 128<\/strong> for internal use (it encodes every printable ASCII character compactly), and EAN-13 \/ UPC-A<\/strong> for retail. Don’t ship a Code 39 barcode in 2026 unless a partner system specifically requires it \u2014 it’s larger and lower density than Code 128 for the same data.<\/p>\n

Check digits \u2014 what they are, why they exist<\/h2>\n

EAN-13, UPC-A, ITF-14, and others end with a check digit computed from the preceding digits using the GS1 modulo-10 algorithm: weight digits alternately by 1 and 3, sum, and pick the smallest digit that makes the total a multiple of 10. This catches single-digit errors and most transposition errors at scan time. Our generator computes the check digit automatically \u2014 paste 12 digits and we add the 13th \u2014 but you can override it if you’re reproducing a specific code that uses a different scheme.<\/p>\n

Code 128 has internal checksums built into the symbology; Code 39 has an optional mod-43 check digit (rarely used outside government).<\/p>\n

How to generate a barcode<\/h2>\n
    \n
  1. Open the barcode generator<\/a><\/li>\n
  2. Pick a symbology (Code 128 if unsure)<\/li>\n
  3. Enter your data \u2014 invalid characters are flagged as you type<\/li>\n
  4. Adjust width, height, and “include text below” toggle<\/li>\n
  5. Pick PNG<\/strong> (for digital use) or SVG<\/strong> (for print and labels)<\/li>\n
  6. Click Download<\/strong> \u2014 the file appears in your browser’s downloads folder<\/li>\n<\/ol>\n

    Print quality \u2014 the X-dimension rule<\/h2>\n

    Barcode print quality is governed by the X-dimension<\/strong> \u2014 the width of the narrowest bar. GS1’s published spec sets the X-dimension between 0.264 mm (10 mil) and 0.66 mm (26 mil) for retail. Print at less than 0.2 mm and scanners struggle; below 0.15 mm and scans fail outright. The barcode also needs quiet zones<\/strong> (blank margins) of at least 10\u00d7 X on each side \u2014 squeeze the barcode into a tight box without quiet zones and scanners can’t find the start\/stop characters.<\/p>\n

    For a printed product label aim for X = 0.33 mm (13 mil); for a screen-only QR\/ID barcode, any size that’s at least 200 px wide on a typical phone is fine. SVG output scales without loss, so prefer SVG for anything you’ll print.<\/p>\n

    Common gotchas<\/h2>\n