Why are my lower-case letters printed in capitals?

Standard Code 39 has no lower-case letters. Use Code 128 to keep them.

Do I need the check character?

Only if the system that reads the code expects it. Without it the code is still valid Code 39.

Code 39 barcode generator

Code 39 (Code 3 of 9) is the older alphanumeric barcode still asked for by parts, asset and government systems. It holds upper-case letters, digits, space and - . $ / + %. Lower-case letters are changed to upper case.

Size with quiet zones64.4 × 19.1 mm2.53 × 0.75 in

Fits a 99.1 × 38.1 mm label (A4, 14 per sheet) or 4 × 1 in (Letter, 20 per sheet).

Encoded: PART-0042

64.4 × 19.1 mm

How to use it

Type the text without asterisks; the * start and stop characters are added.
Turn on the modulo-43 check character only if the receiving system expects it.
Code 39 is wide: about 13–16 modules per character. Check the width under the code before printing.

When to use Code 39

Use it when a customer, a government body or legacy software asks for it. For anything new, Code 128 holds more characters in less space.

Full ASCII mode

Some scanners are set to Code 39 Full ASCII, where pairs such as $A or +B stand for other characters. If your text contains a $, +, % or / followed by a letter, those scanners read something different. The generator warns you when that can happen.

Questions

Why are my lower-case letters printed in capitals?: Standard Code 39 has no lower-case letters. Use Code 128 to keep them.
Do I need the check character?: Only if the system that reads the code expects it. Without it the code is still valid Code 39.