What is a Code-39 Full ASCII barcode?
Code 39 Full ASCII, often called extended Code 39, lets the classic Code 39 barcode carry all 128 ASCII characters, including lowercase letters, punctuation and control characters. It is the usual answer when a Code 39 system needs text that standard Code 39 cannot hold.
It uses no new bar patterns. Characters outside the basic 43-character Code 39 set are written as two-character pairs, for example a lowercase letter is a + sign followed by the uppercase letter. The scanner must have Full ASCII mode turned on to turn those pairs back into the original characters; otherwise it will show the raw pairs.
Because extra characters take two symbols each, the barcode grows quickly. If you are not tied to Code 39, Code 128 encodes the full ASCII set natively and is much more compact.
What data can Code-39 Full ASCII hold?
Any of the 128 ASCII characters, including lowercase letters, punctuation and spaces. Accented letters, emoji and other non-ASCII characters are not allowed. The modulo 43 check character is optional.
Recommended size
Keep a quiet zone of at least 10 times the narrowest bar on each side. Every lowercase letter or symbol doubles in width, so keep the text short or use Code 128 for longer strings.
More Linear Codes barcodes
How to Create a Barcode in 3 Steps
Choose a barcode type
Select a category on the left (e.g. Linear Codes), then the exact type like Code-128.
Enter data & customise
Type your data — we check it live and add check digits. Adjust size, font and colors.
Download or print
Get PNG, JPG, SVG, PDF or EPS, or print a full sheet of labels in one click.
Why Use QRCodeChamp Barcode Generator
125+ barcode types
Linear, 2D, GS1, postal, healthcare and payment codes.
Live validation
Friendly errors with one-click fixes and automatic check digits.
Print-ready PDF
Exact mm sizes, label sheets (Avery, A4, 4×6 thermal).
Bulk barcodes
Paste a list or generate number sequences.
Choose the Type of Barcode You Need
Not sure which barcode to use? Start with what you need it for — we’ll pick the right type.
Frequently Asked Questions
Full ASCII Code 39 stores a lowercase a as the pair +A. Turn on Code 39 Full ASCII (extended) mode in your scanner settings so it decodes the pair back to a lowercase letter.
They use the same bars. Standard Code 39 holds uppercase letters, digits and a few symbols, while Full ASCII combines two characters to represent everything else in the ASCII set.
Usually yes. Code 128 encodes all ASCII characters directly, is narrower for the same text and needs no special scanner mode. Use Code 39 Full ASCII when your existing system only reads Code 39.