Guides for codes that actually scan.
Short, honest notes based on the encoders this site uses and on published symbology standards. Where something depends on your printer or your scanner, we say so instead of guessing.
- No signup
- Free commercial use
- No watermarks
Quiet zones: the margin that does the work
A scanner finds a symbol by its clear margin. An ordinary QR code needs four empty modules on every side; Micro QR needs two; 1D barcodes need a wide clear space either side of the bars, listed per format in the barcode format table. Our exports paint that margin in your chosen background colour and never place a logo, caption or frame inside it.
Error correction, in one paragraph
QR codes carry redundant data so a damaged or partly covered symbol still decodes. Level L adds roughly 7% recovery capacity, M about 15%, Q about 25% and H about 30%. Higher levels mean more modules for the same content, so the code gets denser and each module gets smaller at a fixed print size. A centred logo consumes recovery capacity, which is why we raise the level to Q automatically when you add one — and why you should still scan the printed result.
Choosing a symbology
For internal labels, Code 128 handles letters and digits compactly. Retail products use EAN-13 or UPC-A with a number licensed from GS1. Outer cases use ITF-14. Books use ISBN. When space is tight or you need letters in a 2D symbol, Data Matrix is the usual industrial choice; PDF417 appears on identity documents and boarding passes.
Printing
SVG is the only true vector download here, so it is what a print shop should get — it can be scaled to any size. The PDF puts a high-resolution image of the same artwork on the paper size you choose, which is right for printing that page yourself. If you need PNG, export at a size where every module lands on whole pixels — our PNG export disables smoothing for exactly that reason. Print a test at final size and scan it with the oldest device that will realistically be used.