Barcode Types Explained: 1D vs 2D and How to Choose the Right Symbology

Choosing a barcode symbology means matching the data type, scanner hardware, label size, and industry standard you must meet. In Label Toolkit, a free browser-based label designer, you can generate every major 1D and 2D barcode without installing any software. The short answer: use Code 128 for general shipping and logistics, QR or Data Matrix when you need a lot of data in a small area, and UPC-A or EAN-13 for retail point-of-sale scanning.

• 1D barcodes (Code 128, Code 39, UPC, EAN, ITF-14) encode data in parallel bars and are read by virtually every laser scanner in retail and logistics.
• 2D barcodes (QR Code, Data Matrix, PDF417) encode data in a matrix pattern and can store hundreds to thousands of characters in a small footprint.
• The right choice depends on four factors: data capacity, label size, scanner type, and industry compliance requirements.
• Label Toolkit lets you switch symbologies instantly and preview the scannable result before printing or exporting ZPL for a Zebra printer.

What is a barcode symbology?

A barcode symbology is the specific encoding standard that defines how data is converted into a visual pattern a scanner can read. Symbology covers the allowed character set, the way bars or modules are arranged, the checksum algorithm, and the quiet-zone rules. Choosing the wrong symbology means your scanner hardware simply will not read the label, even if the barcode looks visually correct.

1D barcodes: bars, spaces, and linear data

One-dimensional (1D) barcodes encode data horizontally in a series of bars and spaces of varying widths. A single laser line is enough to decode them. Because the beam scans in one axis only, these are also called linear barcodes.

Code 128

Code 128 is the workhorse of shipping and warehouse operations. It encodes the full ASCII 128 character set, including letters, digits, and control characters. A typical 1-inch-wide Code 128 barcode at 203 DPI (dots per inch, the resolution of a standard entry-level Zebra printer) can encode roughly 20 characters at a reasonable density. The minimum bar width at 203 DPI is one dot, or approximately 0.125 mm (0.005 inches). The quiet zone on each side must be at least 10 times the narrowest bar width, so roughly 1.25 mm per side.

GS1-128 is a variant of Code 128 that uses GS1 Application Identifiers to add semantic meaning to the data, for example (01) before a GTIN-14 or (17) before an expiry date. Use GS1-128 when a trading partner or retailer compliance guide requires it.

Code 39

Code 39 predates Code 128 and encodes only 43 characters: uppercase letters, digits 0 through 9, and a handful of symbols. It is self-checking, meaning a built-in structure reduces scanning errors even without a checksum. The trade-off is that it is less dense than Code 128, so the same data takes up more horizontal space. Use Code 39 only when older scanner infrastructure requires it or an industry standard mandates it (some US Department of Defense labeling specifications still reference it).

UPC-A and EAN-13

UPC-A encodes exactly 12 digits; EAN-13 encodes 13. Both are fixed-length retail POS (point-of-sale) symbologies managed by GS1. You cannot use them for free-form data. To put a product on a retail shelf with a scannable barcode that retailers will accept, you need a registered GS1 company prefix. The quiet zone for both is a minimum 9X on the left and 9X on the right, where X is the width of the narrowest bar (typically 0.33 mm in the standard size). Do not shrink UPC or EAN below 80% of nominal size or scanning reliability drops sharply.

ITF-14

ITF-14 (Interleaved 2-of-5, 14 digits) encodes a GTIN-14 on corrugated cardboard shipping cartons. It is specifically designed to scan reliably on rough, printed kraft surfaces where fine detail is lost. The thick bearer bars above and below the barcode prevent short-scans at the edges. If you are labeling a case or pallet, ITF-14 is the GS1-recommended choice.

Code 93

Code 93 is a denser alternative to Code 39 that supports the full ASCII set via shift characters. It is less common but still appears in some courier and asset-tracking workflows. Most modern scanners read it without special configuration.

2D barcodes: matrices, stacks, and high-density data

Two-dimensional barcodes encode data in both the horizontal and vertical axes. A 2D imager (camera-based scanner) captures the entire symbol at once. Laser scanners generally cannot read 2D symbols. If your scanning hardware is older laser-only equipment, stay with 1D symbologies.

QR Code

QR Code (Quick Response) was developed by DENSO WAVE and is now standardized as ISO/IEC 18004. It supports four data modes: numeric (up to 7,089 characters), alphanumeric (4,296 characters), binary (2,953 bytes), and Kanji. Error correction comes in four levels: L (7% recovery), M (15%), Q (25%), and H (30%). The higher the error correction level, the larger the symbol for the same payload, but the more damage it can survive. Use level M for most labels. For printed marketing labels where you want to embed a logo, use level H so the logo blocks do not prevent decoding. Label Toolkit supports all four QR error-correction levels and logo embedding natively.

A QR Code has three finder patterns (the large squares at three corners) and one alignment pattern (on larger versions). The quiet zone must be at least 4 modules wide on all four sides. At a print density of 300 DPI, a single QR module is about 0.085 mm if you use a 1-dot-per-module mapping, or roughly 0.25 mm at a more readable 3-dots-per-module mapping. In ZPL, the ^BQ command sets the QR version and error-correction level; for example, ^BQN,2,M generates a normal-orientation QR at error-correction level M.

Data Matrix

Data Matrix (ECC 200) is the preferred symbology when label real estate is extremely limited. A Data Matrix can encode up to 2,335 alphanumeric characters in a square or rectangular grid as small as 10x10 modules. It is the standard for marking electronic components, medical devices, and aerospace parts because it survives harsh surfaces and can be laser-etched directly onto metal. GS1 DataMatrix is the regulated variant used in healthcare and medical device labeling. The quiet zone is one module on all four sides, much smaller than QR's four-module requirement.

The practical minimum print size for a reliably scannable Data Matrix at 203 DPI is about 10 mm x 10 mm for a 20-character payload. At 300 DPI you can go smaller, around 6 mm x 6 mm, without losing scannability.

PDF417

PDF417 is a stacked linear symbology (it looks like multiple 1D barcodes stacked vertically) that encodes up to 1,850 ASCII characters or 2,710 digits. It is required on US driver's licenses (AAMVA standard) and airline boarding passes (IATA standard). It needs a 2D imager to decode. Unless you are producing ID documents or boarding passes, QR or Data Matrix will serve better in almost every other scenario.

1D vs 2D at a glance

How to choose a barcode symbology: a step-by-step decision process

1. Identify your data payload. Count the characters you need to encode and note whether they are digits only, alphanumeric, or full ASCII with special characters. A 12-digit product number fits comfortably in Code 128 or UPC. A full URL with 80 characters needs QR or Data Matrix.
2. Check scanner hardware. If your warehouse or retail partner uses laser scanners exclusively, you must use a 1D symbology. If scanners are modern camera-based imagers, 1D and 2D both work.
3. Measure available label space. If the printable area is smaller than about 15 mm x 10 mm and you need more than 20 characters, choose Data Matrix. If space is generous, Code 128 is simpler to implement.
4. Check industry and compliance requirements. Retail shelf products in most countries require UPC-A or EAN-13 from a registered GS1 prefix. Amazon FBA uses a FNSKU barcode in Code 128 format. Healthcare serialization under the US Drug Supply Chain Security Act (DSCSA) requires GS1 DataMatrix or GS1-128. Automotive parts often use Data Matrix per customer specifications.
5. Factor in print resolution. At 203 DPI (the standard for budget Zebra printers), narrow bars are 0.125 mm. At 300 DPI, 0.085 mm. Very small 2D symbols printed at 203 DPI may fall below the minimum module size for reliable scanning. When in doubt, print a test label and verify with a real scanner before committing to a production run.
6. Consider human readability. 1D barcodes are traditionally printed with the human-readable interpretation (the digits or text) beneath the bars. 2D symbols have no built-in human-readable equivalent. If operators need to visually verify a barcode number at a glance, place a text field beneath a 2D symbol or use a 1D format.
7. Generate and test in Label Toolkit. Open the designer, drop in a barcode element, switch symbologies from the panel, type your payload, and preview the result. Export as a vector PDF for offset printing or as ZPL for a Zebra thermal printer and scan the output with a verification tool before printing at scale.

Quiet zones: the invisible requirement that breaks most labels

A quiet zone is the blank margin around a barcode that separates it from surrounding graphics or text. Scanners use the quiet zone to know where the symbol starts and ends. Violating quiet-zone minimums is one of the most common reasons a barcode fails to scan in production even though it looks fine on screen.

Quiet-zone rules by symbology:

• Code 128 / GS1-128: 10X on each side (X = narrowest bar width, typically 0.254 mm at 203 DPI), so about 2.54 mm per side minimum.
• UPC-A / EAN-13: 9X left, 9X right (roughly 3 mm at nominal size).
• ITF-14: 10X on all sides.
• QR Code: 4 modules on all four sides.
• Data Matrix: 1 module on all four sides.

Label Toolkit automatically enforces quiet zones when you place a barcode element, so surrounding graphics cannot overlap the required margin.

Barcode size and print resolution in practice

The DPI (dots per inch) or DPMM (dots per millimeter) of your printer directly controls the minimum reliable barcode size. At 203 DPI (8 DPMM), one printed dot is 0.125 mm. At 300 DPI (12 DPMM), one dot is 0.085 mm. At 600 DPI (24 DPMM), one dot is 0.042 mm.

For a Code 128 barcode at 203 DPI encoding a 20-character alphanumeric string, expect a printed width of around 50 mm (2 inches) at a bar-width ratio of 2:1 (wide to narrow). For the same data in Data Matrix at 203 DPI using a 24x24 symbol, the footprint is roughly 9 mm x 9 mm. That is why 2D symbologies appear on tiny pharmaceutical labels where a 1D barcode would be physically impossible.

Generating barcodes in Label Toolkit vs writing raw ZPL

When you need to print on a Zebra thermal printer, you have two paths. The visual path is to design the label in Label Toolkit and let it generate the ZPL automatically. The code path is to write ZPL directly. For reference, a Code 128 barcode in ZPL looks like this:

^XA
^FO50,50
^BCN,80,Y,N,N
^FD>:SHIPMENT-12345^FS
^XZ

Here, ^FO50,50 sets the field origin 50 dots from the left and 50 dots from the top. ^BCN,80,Y,N,N calls the Code 128 command with normal orientation, a 80-dot height, human-readable text below (Y), no check digit printed separately (N), and no UCC check digit (N). ^FD feeds the data and ^FS closes the field. For QR Code, you would swap to ^BQN,2,M before the ^FD command.

For a deeper look at how those commands work, see the ^BC ZPL command reference for Code 128 and the ^BQ ZPL command reference for QR Code. Both pages include copy-paste examples and parameter-by-parameter explanations.

Industry-specific symbology quick reference

Common mistakes when choosing a barcode symbology

• Using QR when the scanner is laser-only. QR requires a 2D imager. A laser scanner will not decode it, and the error is silent: the scanner just will not beep.
• Shrinking UPC or EAN below 80% magnification. The GS1 specification allows 80% to 200% of nominal size. Below 80%, bar widths fall below the minimum and scanning reliability collapses.
• Encoding non-ASCII characters in Code 39. Code 39 supports only uppercase A to Z, digits 0 to 9, and the characters space, minus, plus, slash, period, and dollar. Lowercase letters will silently truncate or error.
• Ignoring quiet zones. Placing a border or graphic too close to a barcode is probably the single most common production failure. Budget the quiet zone first, then size the barcode to fit what remains.
• Printing a 2D code too small at low DPI. A Data Matrix with a 10x10 module grid at 203 DPI needs each module to be at least 2 dots (0.25 mm) to scan reliably. That gives a minimum symbol size of about 5 mm. Go smaller and you are gambling on scanner quality.

For a broader look at every major barcode type with visual examples and advanced use cases, see the complete barcode types guide in the Label Toolkit barcode cluster.

Frequently asked questions

What is the difference between a 1D and 2D barcode?

A 1D barcode encodes data in a single horizontal row of bars and spaces; any laser or camera scanner can read it. A 2D barcode encodes data in a grid of squares or dots in both directions, holds far more data, and requires a camera-based imager to decode. Choose 1D for simplicity and wide scanner compatibility; choose 2D when data volume or label space demands it.

Which barcode symbology should I use for shipping labels?

Code 128 or GS1-128 is the standard for shipping labels. Code 128 handles any alphanumeric payload up to around 80 characters reliably. If your trading partner requires GS1 Application Identifiers (for GTIN, lot number, expiry date, and so on), use GS1-128, which is a constrained version of Code 128 with an FNC1 character at the start.

Can I use a QR code instead of a barcode on a product label?

Yes, with caveats. If the label is for retail POS scanning, the checkout scanner almost certainly expects UPC-A or EAN-13, not a QR code. If the label is for inventory tracking, marketing, or consumer information and you control the scanning hardware or it is a smartphone, QR works well. Always verify with your retailer or logistics partner before switching symbologies.

What barcode does Amazon FBA require?

Amazon FBA uses an FNSKU (Fulfillment Network Stock Keeping Unit) barcode printed in Code 128 format. Amazon generates the FNSKU number in Seller Central. You print it on a label sized at least 1 inch by 2 inches (25.4 mm x 50.8 mm) using a 300 DPI thermal printer for reliable scanning at the fulfillment center.

How do I know if my barcode is the right size?

Print one test label, then scan it with the actual scanner hardware that will be used in production. Do not rely on a smartphone test alone if the final scanner is a fixed warehouse imager or laser gun. Most professional barcode verifiers report an ISO grade from A to F; aim for a grade C or better. Label Toolkit generates barcodes at precise sizes based on the module or bar width you set, and the vector PDF export preserves those dimensions exactly at print time.

Ready to generate the right barcode for your label without installing any software? Create a free Label Toolkit account and design, preview, and export your first label in minutes.