Warning
Our POSTNET Barcode Generator enables you to create USPS-compliant barcodes for ZIP Codes, ZIP+4, and delivery point codes with precision. Generate high-quality barcodes in formats like PDF, PNG, SVG, or JPG, perfect for mail automation and bulk mailing needs.
What Is the Ideal Size for a POSTNET Barcode?

The ideal size for a Postnet barcode is determined by its specific application, ensuring it complies with USPS standards for readability and accuracy. Postnet barcodes consist of a series of full and half-height bars used for sorting and routing mail. The standard height of full bars is 1/2 inch (12.7 mm), while half bars are 1/4 inch (6.35 mm). The bar width is typically 0.02 inch (0.5 mm), and the spacing between bars is crucial for accurate scanning.
For proper functionality, the total length of the barcode depends on the number of digits encoded. A standard 11-digit Postnet barcode, including the delivery point, measures approximately 4.125 inches (105 mm). Adequate quiet zones of 1/4 inch (6.35 mm) on both sides ensure clear separation from other elements on the mailpiece.
Maintaining these dimensions is essential for reliable scanning by postal equipment. Deviations in size or spacing can result in unreadable barcodes, potentially delaying mail delivery. Use a quality barcode generator to ensure your Postnet barcodes meet these precise specifications.
What Type of Barcode is POSTNET?
POSTNET (Postal Numeric Encoding Technique) is a linear barcode symbology developed by the United States Postal Service (USPS). It is specifically designed for encoding numeric data, such as ZIP Codes, ZIP+4 Codes, and delivery point codes, to assist in automated mail sorting and routing.
This barcode consists of a series of full and half-height bars. Each digit in the numeric data is represented by a unique combination of five bars, ensuring accurate encoding. The structure of a POSTNET barcode includes the encoded numeric data, a checksum digit for error detection, and start and stop frame bars that define the barcode’s boundaries.
POSTNET is classified as a high-density barcode due to its compact design and ability to encode numeric data efficiently. Although it has been largely replaced by the Intelligent Mail Barcode (IMB) in USPS operations, POSTNET remains a recognised and functional symbology for specific postal applications. Its simplicity, reliability, and compatibility with postal equipment make it a specialised barcode for mail-related processes.
How To Use Our Free POSTNET Barcode Generator?

Using our free POSTNET Barcode Generator is simple and efficient. Start by entering your desired numeric data—typically 5, 9, or 11 digits corresponding to your ZIP Code, ZIP+4 Code, or delivery point code. Ensure the data is accurate to generate a valid barcode.
Once your data is ready, click the “Generate POSTNET Barcode” button. The tool will instantly create your barcode, ensuring it meets USPS specifications for accurate mail sorting and routing.
After generation, you can download the barcode in multiple formats, including PDF, SVG, PNG, or JPG. These options make it easy to integrate the barcode into your digital and printed materials. Designed for reliability and precision, our generator streamlines the creation process, providing high-quality outputs for professional postal applications.
How is the Checksum Calculated for POSTNET Barcodes?

The checksum in a POSTNET barcode ensures the total value of all digits, including the checksum, is divisible by 10. This enables error detection and enhances reliability. Here is a detailed, step-by-step guide with an example:
Sum the Digits:
Add all the individual digits of the ZIP Code, ZIP+4 code, or delivery point code.Calculate the Modulo 10:
Divide the sum obtained in Step 1 by 10 and note the remainder. This remainder identifies how much is needed to make the sum a multiple of 10.Compute the Checksum:
Subtract the remainder from 10. The result is the checksum digit. If the remainder is 0, the checksum will also be 0.Append the Checksum:
Add the checksum digit to the end of the original ZIP Code, ZIP+4 code, or delivery point code. This final number is then encoded in the POSTNET barcode.
Let’s understand this better using an example
Suppose we have a ZIP+4 code “12345-6789,” here is how we calculate its checksum:
Sum the Digits:
Add all the digits together:
1+2+3+4+5+6+7+8+9=451 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 451+2+3+4+5+6+7+8+9=45.
Calculate the Modulo 10:
Divide the sum (45) by 10:
45÷10=445 \div 10 = 445÷10=4 remainder 5.
Compute the Checksum:
Subtract the remainder from 10:
10−5=510 – 5 = 510−5=5.
The checksum digit is 5.
Append the Checksum:
Add the checksum digit to the end of the ZIP+4 code:
Original ZIP+4: 12345-6789.
Complete sequence with checksum: 1234567895.
This sequence, including the checksum, is used to generate the POSTNET barcode. It ensures that the total sum (including the checksum) is divisible by 10, which facilitates error detection during mail processing.
What is the Character Limit of Your POSTNET Barcode Generator?

Our Postnet Barcode Generator is designed to support the encoding of numeric data required by USPS standards for postal barcodes. The character limit corresponds to the type of postal code being used:
5-Digit ZIP Code: The generator supports exactly 5 numeric characters. This is the most basic version of a Postnet barcode used for standard ZIP Codes.
ZIP+4 Code: For enhanced accuracy in sorting, the generator allows 9 numeric characters, comprising the 5-digit ZIP Code and a 4-digit extension.
Delivery Point Code: For precise delivery point identification, the generator accepts up to 11 numeric characters, including the ZIP+4 Code and an additional 2-digit delivery point.
Each of these options is compatible with the USPS’s requirements for mail routing and sorting. The generator automatically calculates and appends the checksum digit, ensuring that the final barcode includes all necessary components. Using our generator guarantees error-free barcodes suitable for various postal needs.
Is There a Scan Limit to the POSTNET Barcode Generated Using Your Online Generator?
There is no scan limit for the POSTNET barcode generated using our online barcode generator. Once created, the barcode can be scanned an unlimited number of times, provided it is printed or displayed with clarity and adheres to USPS quality standards. This ensures consistent functionality across postal sorting systems, enabling efficient and reliable mail processing.
Do You Have Other Barcode Generators?
Yes, we offer a wide variety of barcode generators. In addition to the Postnet Code generator, you can create barcodes such as QR code, Code 128, Code 39, EAN-13, ITF, and Data Matrix. We also support specialised barcode formats like Aztec code, Maxicode, and PDF 417. Each generator allows you to customise and download barcode images in formats suitable for commercial use. Whether for retail, logistics, or inventory, our tools cater to diverse business needs.