Barcode Generator

What is Barcode Generator?

Free barcode generator. Generate Code128 and EAN-13 barcodes for any text or number. Download as PNG. Works in your browser using JsBarcode. Instant generators for passwords, QR codes, barcodes, and more. TekPulse's Barcode Generator is completely free — no signup, no ads in results, and no data stored on our servers.

How to Use Barcode Generator Online

1. Enter the data to encode: a product number, URL, or text string
2. Select the barcode format: Code 128 (for any text) or EAN-13 (for product barcodes, 13 digits)
3. Adjust the barcode width and height
4. Preview the barcode and check that it scans correctly using your phone camera
5. Download the barcode as an SVG (scalable, best for print) or PNG image

Barcode Generator Formula & Calculation

Different barcode symbologies encode data differently. Code128 (the default here) can encode any ASCII text or number using a variable-width bar pattern, making it the most flexible choice for general use. EAN-13 and UPC-A are fixed-length numeric formats used on retail products: you enter 12 digits and the library computes a 13th 'check digit' using a weighted checksum (odd-position digits counted once, even-position digits counted ×3, summed and taken mod 10) so a scanner can detect a single misread digit. Code39 is an older alphanumeric format still used in logistics and ID badges; ITF-14 is used on shipping cartons; Pharmacode is a specialized format for pharmaceutical packaging verification.

Example: for UPC-A content 03600029145, the checksum of odd/even positions (weighted 1×/3×) determines the final check digit 2, giving the complete 12-digit UPC 036000291452 — if a scanner misreads any single digit, the checksum won't match and the read is rejected rather than silently accepted as wrong data.

Key Factors That Affect Your Result

1. Symbology choice — Code128 accepts any text/number and is the safest general-purpose choice; EAN-13/UPC-A are retail-standard numeric formats required by point-of-sale scanners and must use the correct digit count (12 for UPC-A, 12+check for EAN-13) or generation fails.
2. Check digit validation — The automatic checksum in EAN/UPC formats is what lets a cheap barcode scanner catch read errors (a smudged or misprinted bar) instead of ringing up the wrong product — this is why you can't just type any 12-13 digit number and expect it to be a "real" valid barcode without matching a registered GS1 prefix for actual retail use.
3. Bar width and print size — Lowering the "Width" setting makes bars thinner, fitting more into a given space but increasing the risk of scan failures on lower-quality printers; retail barcodes have minimum size standards for exactly this reason.
4. Human-readable text — Keeping "Show text" enabled prints the encoded digits below the bars, so the code can still be identified or manually keyed in if a scanner fails to read it — standard practice on all commercial packaging.

Why Use TekPulse Barcode Generator?