Code 39 Barcode Generator

Code 39 is a variable-length barcode format that encodes uppercase letters, numbers, and a few special characters. It is one of the oldest barcode standards, first developed in 1974, and remains widely used in non-retail applications.

Code 39 supports only uppercase letters and produces wider barcodes. Code 128 supports the full ASCII set (including lowercase) and creates more compact barcodes. Code 128 is better for space-constrained applications.

No. Code 39 is self-checking, meaning each character includes its own error detection. An optional modulo 43 check digit can be added for extra security, but it is not required.

Standard Code 39 only supports uppercase A-Z. Extended Code 39 (Code 39 Full ASCII) can encode all 128 ASCII characters by combining pairs of standard characters.

Code 39 is universally supported by virtually all barcode scanners, requires no check digit calculation, and is mandated by several industry standards (military, automotive). Its simplicity makes it reliable and easy to implement.

There is no theoretical maximum length, but practical limits depend on the printing width and scanner capability. Most applications keep Code 39 under 20 characters for reliable scanning.