Free Code 39 Barcode Generator

Why Use Our Code 39 Generator?

Generate Code 39 Labels in 3 Steps

When to Use Code 39 Barcodes

What is a Code 39 Barcode?

Code 39 (also written Code 3 of 9) is a discrete, variable-length linear barcode symbology introduced in 1974. Each character is encoded as a pattern of five bars and four spaces, with three of the nine elements being wide — giving the format its '3 of 9' name. The barcode is self-checking and requires no check digit in most implementations.

Although Code 128 has largely superseded Code 39 in modern warehouse and logistics applications due to its higher data density, Code 39 remains the mandated standard in several regulated industries. The US Department of Defense, the automotive industry's AIAG standard, and many healthcare systems specify Code 39 by name in their labeling requirements — making compatibility with this format still essential for suppliers in these sectors.

Code 39 Barcode — Frequently Asked Questions

What is a Code 39 barcode?

Code 39 (also called Code 3 of 9) is a linear barcode that encodes uppercase letters A–Z, digits 0–9, and seven special characters (space, $ + − . / %). It was one of the first alphanumeric barcodes and remains widely used in industries requiring compatibility with older scanning hardware.

What is the difference between Code 39 and Code 128?

Code 128 is more space-efficient and can encode the full 128-character ASCII set, including lowercase letters. Code 39 is limited to 43 characters (uppercase only) and produces physically wider barcodes for the same data. Code 39 is preferred when you need guaranteed compatibility with older or specialized scanners that may not support Code 128.

Does Code 39 require a check digit?

No. A check digit is optional in Code 39 and rarely used in practice. Our generator creates standard Code 39 barcodes without a check digit by default, which is compatible with all Code 39 scanners.

What industries still use Code 39?

Code 39 is standard in the US Department of Defense (MIL-STD-1189), US automotive industry (AIAG standard), healthcare (blood bank labeling), and government asset tracking. Many legacy warehouse management systems were designed around Code 39 and still require it.

Can I generate Code 39 barcodes from an Excel or CSV file?

Yes. Upload your Excel or CSV file, select the column with your values (uppercase letters, numbers, and symbols only — lowercase letters are not supported by Code 39), and generate all barcodes in one batch.

How many characters can a Code 39 barcode store?

Code 39 has no defined maximum length, but practical reliability is best at 10–15 characters. Longer values produce physically wide barcodes that can be harder to scan with narrow-beam scanners. For longer alphanumeric codes, Code 128 is a better choice.