What is a Code 39?

The first alphanumeric barcode to catch on, and still everywhere in defence, automotive and library systems decades after something denser came along. Every character is nine elements wide, three of them wide and six narrow - which is where the name comes from, and why a scanner can read it even when the printing is poor or the ratio is off.

What it holds

Capital letters, digits, space, and the six symbols - . $ / + %. Lower case is folded up to capitals rather than refused. It is roughly three times longer than Code 128 for the same content, so it suits short references: an asset tag, a shelf location, a form number.

Making a lot of them

Drop a .txt or .csv on this page and every line becomes its own Code 39, all of them zipped together. A CSV is read from its first column. Nothing is uploaded - the codes are drawn in this page, on your machine - so a list of five thousand costs nothing and takes as long as your laptop takes.