Free Code 39 Barcode Generator

Code 39 is a linear (1D) barcode symbology that encodes 43 characters: uppercase letters A to Z, digits 0 to 9, space and seven special characters (- . $ / + %). Invented in 1974, it is self-checking and defined in the ISO/IEC 16388 standard.

It remains standard for asset tags, industrial part marking and defense labeling.

Code 39 supports 43 characters:

• Uppercase letters (A to Z)
• Numbers (0 to 9)
• Space and seven special characters: – . $ / + %.

Every barcode also begins and ends with an asterisk (*), the start and stop character, which this generator adds automatically. Extended Code 39 (Full ASCII mode) can represent the full ASCII set, including lowercase letters, using two-character pairs.

No. This Code 39 generator adds the start and stop characters for you. Code 39 marks the beginning and end of every symbol with an asterisk (*), which tells the scanner where the barcode starts and stops.

If you build barcodes with a Code 39 font instead, in Excel or Word, you must add the asterisks yourself by typing *YOURDATA* around each value. A missing asterisk is the most common reason a font-built Code 39 barcode fails to scan.

Standard Code 39 cannot encode lowercase letters. It supports only uppercase A to Z, digits 0 to 9, space and the symbols – . $ / + %.

To encode lowercase letters or the rest of the ASCII set, either use Extended Code 39 (Full ASCII mode) with its two-character pairs or switch to Code 128, which encodes all 128 ASCII characters natively in a shorter symbol.

Most scanners must have Full ASCII mode enabled before they will decode Extended Code 39 correctly.

To generate Code 39 barcodes in Excel, install a Code 39 barcode font such as Google’s free Libre Barcode 39, wrap each cell value in asterisks with a formula like =”*”&A2&”*”, then apply the barcode font to the formula column.

The asterisks are the Code 39 start and stop characters; without them the barcode will not scan. A font workflow suits long spreadsheet lists, while this online Code 39 barcode generator is faster for one-off labels: it adds the asterisks automatically and exports vector SVG that prints sharper than font glyphs.

Code 39 is self-checking: the bar-and-space pattern of each character lets the scanner catch a misprinted or damaged character without a separate checksum, so no check digit is required for general use.

Some specifications add an optional modulo 43 check digit anyway: LOGMARS (the U.S. military application of Code 39, defined in MIL-STD-1189) and the HIBC standard used in healthcare labeling both require it.

This Code 39 barcode generator produces standard Code 39 without a check digit, which any compliant reader scans.

Code 39 barcodes are commonly used in:

• Inventory and asset tracking
• Manufacturing and automotive supply chains (AIAG labeling standards)
• Government and defense applications (the U.S. military’s LOGMARS program is built on Code 39)
• Healthcare labeling systems (the HIBC standard)

The key benefits of Code 39 barcodes include:

• Simple and widely supported format
• Easy to generate and scan
• Self-checking by design; no check digit needed for general use
• Suitable for a variety of industrial uses

Code 39 has some drawbacks:

• Lower data density compared to Code 128
• Requires more space for the same amount of data
• Limited character set (unless using Extended Code 39)

Yes. To generate Code 39 barcodes in bulk, use a Code 39 barcode font with the asterisk formula in Excel, which turns a whole spreadsheet column of part numbers into scannable barcodes at once; this free Code 39 barcode generator is built for one-off barcodes with clean SVG export.

For production labeling, generating the images is the smaller half of the job: Camcode pre-prints sequential Code 39 labels on anodized aluminum and durable polyester stock that stays scannable through heat, abrasion and chemicals for the life of the asset.

Request a free sample kit or talk to a labeling specialist for volume runs.