Free Code 39 Barcode Generator
Make a Code 39 barcode from upper-case letters, digits and a few symbols — no Libre Barcode font, no asterisks to type. Download PNG or SVG in seconds.
选择条形码格式
输入内容
调整外观
预览条形码
贴在商品标签上的效果
Overview
What is a Code 39 barcode?
A Code 39 barcode (also called Code 3 of 9) is one of the oldest alphanumeric linear barcodes. It encodes 43 characters: upper-case A–Z, digits 0–9, space and the symbols - . $ / + %. Each character is made of nine elements, three of them wide, which makes the code easy to print and read even with simple equipment.
It is still required in many industries — automotive (AIAG), defense (LOGMARS), healthcare and government ID cards — and is common for internal labels. Code 39 is less compact than Code 128, so codes get long, but its simplicity is the reason it remains popular. The generator adds the start and stop asterisks for you.
Because each character is encoded on its own, the code needs no check digit to be reliable, and scanners decode it even when printing is uneven. The trade-off is width: a ten-character value needs far more space than in denser formats, so plan your label size before committing to it.
Use cases
Where Code 39 is still used
Mostly industries with long-standing standards and internal systems.
Automotive parts
Supplier labels following AIAG standards often specify this format.
Defense and government
US military LOGMARS labels and many ID cards use it.
Employee badges
Simple ID numbers on badges for time clocks and access control.
Libraries
Many library systems still print patron and book labels this way.
Internal labels
Bin locations, file folders and work orders in small warehouses.
Healthcare
Older hospital systems use it for specimen and patient labels.
How it works
How to create a Code 39 barcode
Skip the font install and the formula tricks.
- 1
Choose Code 39
It is preselected on this page. You can switch to Code 128 if your scanner supports it and you need lower-case letters.
- 2
Type your value
Use A–Z, 0–9, space and - . $ / + %. Lower-case letters are converted to upper case. No asterisks needed.
- 3
Download
Set height, colors and the text line, then download PNG or SVG.
Best practices
Tips for Code 39 labels
It is forgiving, but long values need room.
Plan for the width
Each character adds roughly 13 bar widths. Keep values short or use Code 128 for long IDs.
Match your scanner settings
Some scanners need Code 39 enabled or “full ASCII” mode turned off. Test with the device you will use.
Prefer vector for print
SVG keeps the wide-to-narrow bar ratio exact, which matters for this format.
Check the industry spec
Automotive and defense labels define exact bar widths, text position and label layout. Read the specification your customer sends before you design the label.
Keep a clear text line
Most labels in this format print the value underneath for people to read. Leave it on unless your label layout puts the value elsewhere.
Use the optional check digit only when asked
A modulo-43 check digit adds safety but changes the code. Add it only if the receiving system expects it, otherwise scans return an extra character.
FAQ
Frequently asked questions
What is a Code 39 barcode?
- A Code 39 barcode is an alphanumeric linear barcode that encodes upper-case letters, digits and a few symbols. It is simple, self-checking and widely used in automotive, defense and internal labeling.
How do I create a Code 39 barcode?
- With Code 39 selected above, type your value and download the PNG or SVG. Start and stop characters are added automatically.
Do I need the Libre Barcode 39 font?
- No. Fonts require you to wrap the text in asterisks and only work inside your document. The generator gives you an image that works anywhere.
How do I add Code 39 to Excel?
- You can install a Code 39 font and wrap cells with asterisks, or insert images generated here. Images avoid font issues when files are shared.
Can Code 39 encode lower-case letters?
- Standard Code 39 cannot. Full ASCII Code 39 can, using two-character combinations, but Code 128 is the better choice for mixed case.
Does Code 39 need a check digit?
- No, it is self-checking. A modulo-43 check digit is optional and only used when a specification requires it.
Code 39 or Code 128?
- Code 128 is more compact and supports all characters. Use Code 39 when a customer, industry standard or existing scanner setup requires it.
What scanner reads Code 39?
- Almost every laser and imaging barcode scanner reads it, and most phone scanner apps do too. Some devices need it enabled in their settings.
What characters can I use?
- A–Z, 0–9, space and the symbols - . $ / + %. Anything else is rejected with an error so you can fix it before printing.
Why is my code so long?
- Code 39 uses more space per character than other formats. Shorten the value, reduce the bar width carefully, or switch to Code 128.
Is this Code 39 barcode generator free?
- Yes. Unlimited codes, PNG and SVG, no watermark and no sign-up.
Is “3 of 9” the same thing?
- Yes. Code 3 of 9 is the original name: each character has three wide elements out of nine.
How do I scan Code 39 with a phone?
- Most free barcode scanner apps support it. Hold the phone parallel to the label and close enough that the code fills about two thirds of the screen width.
What is LOGMARS?
- LOGMARS is the US Department of Defense labeling standard that uses Code 39 for parts and equipment. It specifies sizes and placement on top of the barcode itself.
Can I print Code 39 on a regular office printer?
- Yes. Its wide and narrow bars are forgiving, so laser printers work well. Print at 100% scale and avoid fit-to-page options that distort the bar ratio.
What is the difference between standard and full ASCII mode?
- Standard mode encodes 43 characters. Full ASCII mode combines two symbols to represent any ASCII character, including lower case. Both sides must use the same mode, so only enable it when your scanner is set up for it.