What Is a 1D Barcode? Complete Guide to Linear Barcodes

If you've ever purchased groceries, received a shipping package, or checked out a book from a library, you've already used a 1D barcode, also known as a linear barcode.

Although QR Codes have become increasingly popular, 1D barcodes remain the world's most widely used automatic identification technology. Millions of products are scanned every day using these simple yet highly reliable barcode symbols.

In this guide, we'll explain what a 1D barcode is, how it works, where it is used, its advantages and limitations, and how it compares with newer 2D barcode technologies.

What Is a 1D (Linear) Barcode?

A 1D barcode is a series of parallel black bars and white spaces of varying widths that represent data.

Unlike a QR Code, which stores information both horizontally and vertically, a 1D barcode stores information only in one direction (left to right).

This is why it is called a Linear Barcode.

The barcode itself does not contain words or numbers. Instead, each combination of bars and spaces represents characters according to predefined barcode standards.

Illustration

Human Readable Text

 

Scanner reads this direction →

Why Is It Called a Linear Barcode?

The scanner reads the barcode across a single horizontal line.

The laser or imaging scanner measures:

• Width of each black bar
• Width of each white space
• Start pattern
• Stop pattern

It converts these measurements into numbers and letters.

Unlike QR Codes, there is no vertical information.

How Does a 1D Barcode Work?

Every barcode follows a simple process.

Step 1 – Data Encoding

The barcode software converts these characters into a pattern of bars and spaces.

Step 2 – Printing

The barcode is printed onto:

• Product labels
• Shipping labels
• Inventory tags
• Asset labels
• Retail packaging

Step 3 – Scanning

The scanner shines a laser or LED light across the barcode.

Dark bars absorb light.

White spaces reflect light.

The scanner measures these reflections.

Step 4 – Decoding

The barcode scanner converts the pattern back into the original information.

Example:

Bars → Decoder → 123456789012

The connected computer then retrieves product information from a database.

Components of a Linear Barcode

Every 1D barcode consists of several important parts.

Quiet Zone

The blank space before and after the barcode.

Without it, scanners may fail.

(See our article What Is a Quiet Zone in a Barcode?)

Start Character

Indicates where the barcode begins.

Data Characters

The actual encoded information.

Check Digit (Some Symbologies)

Used to verify that the barcode has been read correctly.

Stop Character

Indicates the end of the barcode.

Common Types of 1D Barcodes

Code 128

One of the most popular barcode types.

Features:

• High density
• Supports all ASCII characters
• Excellent for logistics
• Used worldwide

Applications:

• Shipping
• Warehouses
• Manufacturing
• Healthcare

Code 39

One of the oldest barcode standards.

Supports:

• Letters
• Numbers
• Some symbols

Used in:

• Military
• Automotive
• Asset tracking

EAN-13

The international retail barcode.

Found on nearly every supermarket product.

Contains:

• Country code
• Manufacturer code
• Product code
• Check digit

UPC-A

Common in North America.

Mostly used in:

• Retail
• Grocery stores

Interleaved 2 of 5 (ITF)

Designed for numeric data.

Popular in:

• Cartons
• Warehouse labels
• Logistics

Codabar

Used mainly in:

• Blood banks
• Libraries
• Medical laboratories

Advantages of 1D Barcodes

Simple

Easy to generate and print.

Low Cost

Requires minimal printing quality.

Fast Scanning

Laser scanners can decode almost instantly.

Reliable

When printed correctly, accuracy exceeds 99.9%.

Universally Supported

Almost every barcode scanner supports major 1D barcode standards.

Limitations of Linear Barcodes

Despite their popularity, linear barcodes have limitations.

Limited Data Capacity

Most linear barcodes store only:

• Product numbers
• IDs
• Serial numbers

They cannot store large amounts of information.

Requires Database Lookup

The barcode usually stores only an identification number.

The computer must retrieve the actual product information.

Requires Horizontal Space

Long data means a physically wider barcode.

Easily Damaged

A scratch across the barcode can prevent scanning.

Where Are 1D Barcodes Used?

They appear almost everywhere.

Retail

• Supermarkets
• Department stores
• Convenience stores

Warehouses

• Pallets
• Cartons
• Shelf labels

Logistics

• Shipping labels
• Courier parcels
• Freight tracking

Manufacturing

• Production tracking
• Work orders
• Component identification

Healthcare

• Patient wristbands
• Laboratory samples
• Medical equipment

Libraries

• Books
• Membership cards

Asset Management

• Office equipment
• Computers
• Tools

How Much Data Can a 1D Barcode Store?

It depends on the barcode type.

Typical capacity:

Barcode	Capacity
Code 39	Up to about 43 characters
Code 128	Around 80+ characters (depending on size)
EAN-13	13 digits
UPC-A	12 digits
ITF	Numeric only

Although some symbologies support longer strings, practical limits depend on label size, print resolution, and scanner capabilities.

Best Practices for Printing 1D Barcodes

To ensure reliable scanning:

• Leave sufficient quiet zones.
• Use high-contrast colors (black on white is ideal).
• Print at an appropriate resolution.
• Avoid stretching or compressing the barcode disproportionately.
• Keep the barcode clean and free from scratches.
• Test with the intended scanner before mass production.

1D Barcode vs 2D Barcode

Feature	1D Barcode	2D Barcode
Data Direction	Horizontal only	Horizontal and vertical
Shape	Long rectangle	Square or rectangle
Storage Capacity	Low	Very high
Error Correction	Minimal	Built-in (varies by symbology)
Typical Examples	Code 128, Code 39, EAN-13	QR Code, Data Matrix, PDF417
Scanner Type	Laser or imaging scanner	Imaging scanner or camera

When Should You Use a 1D Barcode?

A 1D barcode is the best choice when:

• You only need to encode a product ID or serial number.
• Fast scanning is important.
• Labels are narrow but have enough horizontal space.
• Compatibility with existing laser scanners is required.
• You need a cost-effective and proven solution.

If you need to store more information directly in the symbol, such as URLs, contact details, or manufacturing records, a 2D barcode may be more suitable.

Frequently Asked Questions (FAQ)

Is a 1D barcode the same as a linear barcode?

Yes. The terms 1D barcode and linear barcode refer to the same type of barcode.

Can a smartphone scan a 1D barcode?

Yes. Most modern smartphones can scan common 1D barcodes using the camera, although dedicated barcode scanners are generally faster and more reliable in commercial environments.

Which is the most common 1D barcode?

For retail products, EAN-13 (globally) and UPC-A (North America) are the most common. In logistics and warehousing, Code 128 is widely used.

Can a 1D barcode store text?

Yes. Some symbologies, such as Code 128 and Code 39, can encode letters, numbers, and certain symbols.

Are 1D barcodes becoming obsolete?

No. While 2D barcodes are growing in popularity, 1D barcodes continue to be used extensively in retail, logistics, manufacturing, healthcare, and many other industries due to their simplicity, speed, and widespread compatibility.

Final Thoughts

For over 50 years, 1D barcodes have been the backbone of automatic identification systems. They are simple, inexpensive, fast to scan, and supported by virtually every barcode scanner on the market.

Understanding how linear barcodes work, their strengths, and their limitations will help you choose the right barcode for your products, inventory, or business processes. Even as 2D barcodes become more common, 1D barcodes remain an essential technology across countless industries.