Using POSTNET in Small Business Shipping: A Beginner’s Guide

Introduction

For small businesses that mailed invoices, invoices, marketing flyers, or product catalogs, POSTNET was once an essential tool for improving delivery speed and reducing postage costs. Although most mailers now use the Intelligent Mail Barcode, the practices developed around POSTNET are still useful for understanding modern postage requirements and for maintaining legacy systems. This beginner-friendly guide explains how POSTNET was used in small business shipping, what steps were involved, and practical tips and common mistakes to avoid.

Why Small Businesses Used POSTNET

Small businesses used POSTNET for three main reasons:

• Automation discounts: The USPS offered lower postage rates for mail that met automation standards, including properly formatted barcodes.
• Faster, more reliable delivery: Barcoded addresses could be machine-sorted deeper into the postal network, reducing handling time and misrouting.
• Operational simplicity: Once set up, printing barcodes on envelopes was automated and required minimal ongoing effort.

Step-by-step Process for Using POSTNET

1. Address cleansing and ZIP+4 appending: Start by validating and standardizing your address list using address verification software. This step adds ZIP+4 codes and, where available, delivery-point digits. Accurate input data is the most important factor for successful barcode use.
2. Calculate the check digit: POSTNET requires a check digit so the sum of all digits is a multiple of 10. Many address tools and mail software automatically compute this.
3. Generate the barcode: Use mail-merge or postal software to convert the numeric string (ZIP or ZIP+4 plus check digit) into the tall/short bar pattern of POSTNET. Software controls bar widths, heights, and spacing per USPS specs.
4. Place the barcode on the envelope: Position the barcode in the lower-right corner of the address side, allowing required quiet zones (blank margins) and keeping it free from other marks, labels, or return addresses that might obscure reading.
5. Print quality control: Use a high-contrast printer and approved fonts. Periodically test-read samples to ensure postal scanners can decode your printed POSTNET bars. Keep printer heads clean and use the recommended ink tones (dark bars on a light background).
6. Ship and track: While POSTNET itself doesn’t carry tracking data, mail processed through automated channels generally moves faster. For tracked services, pair POSTNET addressing with the appropriate USPS service options.

Practical Tools and Software

Small businesses typically relied on either desktop mailing software or integrated e-commerce platforms to handle POSTNET generation. Programs checked addresses, appended ZIP+4, added the check digit, and produced print-ready barcode graphics. Today, modern shipping platforms automatically create Intelligent Mail Barcodes, so updating to current software is advisable. If you must work with legacy POSTNET systems, verify that software is up-to-date and that you can export the barcode in a clean graphic format for printing.

Best Practices

• Always validate and standardize addresses before encoding—garbage in yields garbage out.
• Follow USPS print specs for bar height, width, and quiet zones to avoid unreadable barcodes.
• Test print and scan batches before sending large mailings. Keep a sample to reference if the postal service has questions.
• Document your process so others can reproduce quality results when staff change.

Common Mistakes to Avoid

Several common errors reduce barcode readability and cost businesses money:

• Poor print contrast—light or fuzzy bars that scanners cannot read.
• Incorrect placement—barcodes too close to the edge, stamps, or other markings.
• Outdated address lists—sending to unverified addresses means incorrect ZIP+4 codes and misrouting.
• Using non-compliant printers—some low-cost printers do not maintain precise bar dimensions.

Costs and ROI

Implementing barcode printing required modest one-time setup costs (software, possibly a printer upgrade) and small ongoing operational effort. The return on investment came from reduced postage rates and fewer delivery delays or returns. For many small mailers, automation discounts and improved customer experience justified the investment.

Modern Alternatives and Migration

If your small business still encounters legacy POSTNET requirements, consider migrating to the Intelligent Mail Barcode (IMb). IMb combines routing, tracking, and service information in one symbol and is the USPS standard today. Most modern shipping platforms and postage meters support IMb and automate the migration, making it a straightforward upgrade for businesses that want tracking and richer data.

Conclusion

POSTNET was a straightforward solution that helped small businesses save on postage and improve delivery reliability by encoding ZIP information into barcodes. Understanding the steps—address validation, check digit calculation, barcode generation, and quality printing—remains valuable, whether you’re dealing with legacy mailings or transitioning to modern barcode standards like IMb. With careful setup and attention to print quality, barcoded mail produces consistent benefits for small business shipping operations.