USPS East Boston Padded Flat Rate Envelope Size Number – Dimension Customer Care Number | Toll Free Number

The United States Postal Service (USPS) has long been the backbone of American mail and package delivery, serving millions of households and businesses across the nation. Among its most popular and cost-effective shipping solutions is the Padded Flat Rate Envelope — a durable, pre-priced shipping option designed for lightweight, non-fragile items that need extra protection. While the USPS operates nationwide, the East Boston Processing and Distribution Center plays a pivotal role in handling high-volume shipments, particularly those originating from or destined for the Greater Boston metropolitan area. This article provides a comprehensive guide to the USPS East Boston Padded Flat Rate Envelope — including its exact dimensions, official size number, customer support contacts, toll-free numbers, and how to access reliable assistance when needed. Whether you're a small business owner, an e-commerce seller, or an individual shipping personal items, understanding the specifics of this envelope and how to reach USPS support can save you time, money, and frustration.

Introduction to USPS East Boston Padded Flat Rate Envelope: Size, Number, and Dimension

The USPS Padded Flat Rate Envelope is one of the most widely used shipping tools in the United States. It is designed to offer a flat, predictable shipping rate regardless of weight (up to 70 pounds) or destination within the U.S., making it ideal for shipping documents, clothing, small electronics, books, and other lightweight but sensitive items that require cushioning. The “East Boston” designation refers not to a unique product variant, but to the major USPS processing facility located in East Boston, Massachusetts — one of the largest and busiest distribution centers in New England.

Historically, the East Boston Processing and Distribution Center was established in the early 20th century to manage the growing volume of mail and parcels entering and exiting the Boston region. As the port city of Boston became a hub for international trade and domestic commerce, the facility evolved into a critical node in the USPS network. Today, it processes over 3 million pieces of mail and packages daily, including thousands of Padded Flat Rate Envelopes shipped from retailers, online sellers, and individuals across Massachusetts, Rhode Island, New Hampshire, and beyond.

The official size and dimension of the USPS Padded Flat Rate Envelope are standardized nationwide. The envelope measures 12-1/2 inches by 9-1/2 inches when flat, and when sealed, it forms a 3/4-inch thick padded packet. The USPS assigns this envelope the official product code “

12-1/2 x 9-1/2” or “Padded Flat Rate Envelope (Medium).” It is important to note that USPS does not assign unique size numbers by region — so the envelope used in East Boston is identical in size and structure to those used in Los Angeles, Chicago, or Miami. The “East Boston” reference in searches often stems from local customers seeking support from the regional center, not from a different envelope type.

This envelope is especially popular among industries such as e-commerce, fashion retail, book publishing, healthcare (for medical records and samples), and educational institutions. Its padded interior protects contents from bending or tearing, while its flat-rate pricing eliminates the need for weight-based calculations. For businesses shipping high volumes, the predictability and reliability of this envelope have made it a staple in logistics planning.

Why USPS East Boston Padded Flat Rate Envelope Size Number – Dimension Customer Support is Unique

Customer support for USPS shipping products, including the Padded Flat Rate Envelope, is not region-specific in terms of product details — but the East Boston facility’s support infrastructure is uniquely positioned to serve a dense, high-volume customer base. Unlike rural or smaller regional centers, the East Boston Processing Center handles a disproportionate number of commercial shipments, which necessitates a more robust and specialized customer service framework.

First, the East Boston center operates extended hours, including weekends and holidays, to accommodate the demands of e-commerce fulfillment centers and retail distribution hubs located in the Boston metro area. This means that if you're a business shipping hundreds of envelopes daily, you can access real-time support outside traditional 9-to-5 hours — a rarity in many other postal service centers.

Second, the support team at East Boston is trained to handle complex logistical issues specific to high-volume shippers. Whether you're troubleshooting a mislabeled envelope batch, reporting a delivery delay affecting a large order, or needing clarification on dimensional weight rules for padded envelopes, the East Boston customer care specialists have direct access to internal tracking systems and regional delivery logs. This level of access is often unavailable through national toll-free lines, which route callers to generic call centers.

Third, the East Boston center maintains a dedicated liaison program for local business associations, including the Boston Chamber of Commerce and the Massachusetts Small Business Development Center. These partnerships allow for direct feedback loops, where customer concerns about envelope dimensions, packaging integrity, or delivery delays are escalated and resolved at the operational level — not just documented and passed along.

Additionally, because East Boston is a major international mail gateway (handling inbound and outbound international shipments via nearby Logan International Airport), the support staff is well-versed in customs documentation, international shipping restrictions, and how padded envelopes interact with global postal regulations. This makes them uniquely qualified to assist customers who are shipping internationally using domestic flat rate envelopes — a common point of confusion.

Finally, the East Boston facility has invested in digital support tools, including live chat integration with the USPS website and regional QR-code-based help kiosks at local post offices. These tools allow customers to scan a code on their envelope packaging and instantly access troubleshooting guides, dimension verification tools, and direct links to East Boston-based support agents — a feature not available at most other USPS centers.

Key Differentiators of East Boston Customer Support

• Extended operating hours for customer inquiries
• Dedicated business liaison program for high-volume shippers
• Direct access to regional tracking and delivery data
• Expertise in international shipping via domestic envelopes
• On-site digital support kiosks and QR-code assistance
• Proactive resolution of batch-level shipping errors

USPS East Boston Padded Flat Rate Envelope Size Number – Dimension Toll-Free and Helpline Numbers

When you need immediate assistance regarding the USPS Padded Flat Rate Envelope — whether it’s about dimensions, delivery delays, damaged envelopes, or incorrect labeling — you have several official toll-free numbers at your disposal. While the USPS operates a national customer service system, the East Boston facility routes specific inquiries through designated lines optimized for New England customers.

Here are the official toll-free numbers associated with USPS support for the Padded Flat Rate Envelope, including those managed by the East Boston Processing Center:

• USPS National Customer Care (General Inquiries): 1-800-275-8777
• USPS Business Customer Support (High-Volume Shippers): 1-800-344-7779
• East Boston Regional Support Line (Specialized Envelope Assistance): 1-833-442-1712
• USPS Track & Confirm (Envelope Tracking): 1-800-222-1811
• USPS Mail Recovery Center (Lost or Damaged Envelopes): 1-800-275-8777 (select option 3)

The East Boston Regional Support Line (1-833-442-1712) is the most critical number for customers seeking specific guidance on the Padded Flat Rate Envelope. This line is staffed by agents trained exclusively in envelope specifications, dimensional compliance, and regional delivery patterns. It is especially useful if you’re unsure whether your item fits within the 3/4-inch thickness limit or if you’re experiencing inconsistent pricing at your local post office.

Important Note: The number 1-833-442-1712 is not a general customer service line. It is reserved for inquiries directly related to packaging dimensions, flat rate envelope compliance, and East Boston-specific delivery anomalies. Calls to this number are prioritized and routed to agents who have direct access to the East Boston facility’s internal envelope audit logs — allowing them to verify whether your envelope was scanned, processed, or flagged for dimensional issues.

For businesses shipping more than 50 envelopes per week, the Business Customer Support line (1-800-344-7779) offers access to account managers who can provide volume discounts, custom labeling solutions, and pre-approval for oversized or borderline padded envelopes. Many East Boston-area e-commerce businesses use this line to pre-clear shipments before sending bulk batches.

Always verify the legitimacy of any phone number you use. Scammers often create fake USPS helplines. The only official USPS toll-free numbers are listed on the USPS.gov website. Never provide payment information or personal details over the phone unless you initiated the call using one of the numbers above.

Best Practices for Calling USPS East Boston Support

• Have your tracking number ready — even if the envelope is undelivered.
• Measure your envelope before calling. Confirm it is 12-1/2" x 9-1/2" and no thicker than 3/4".
• Have your shipping receipt or label printout available.
• Call during business hours (8:00 AM – 8:00 PM ET) for faster response.
• Use the East Boston Regional Line (1-833-442-1712) for dimensional questions only.
• For complaints about delivery delays, use 1-800-275-8777 and request escalation to the East Boston Operations Team.

How to Reach USPS East Boston Padded Flat Rate Envelope Size Number – Dimension Support

Reaching USPS support for the Padded Flat Rate Envelope is not limited to phone calls. The USPS offers multiple channels to ensure customers can access help in the way that best suits their needs. Below is a step-by-step guide to contacting support using each available method, with special emphasis on the East Boston-specific resources.

1. Phone Support

As detailed above, the East Boston Regional Support Line (1-833-442-1712) is your best option for envelope dimension questions. When you call:

• Press 1 for “Packaging and Envelope Specifications.”
• Press 2 for “Flat Rate Envelope Issues.”
• Enter your ZIP code when prompted — this routes you to East Boston agents if you’re in Massachusetts, Rhode Island, Connecticut, or New Hampshire.
• Have your envelope dimensions ready — measure the length, width, and thickness in inches.

Wait times average 3–7 minutes during business hours. If you’re on hold for more than 10 minutes, hang up and try the online chat option.

2. Online Chat via USPS Website

Visit www.usps.com and click “Contact Us” in the footer. Select “Live Chat” and type “Padded Flat Rate Envelope dimensions” or “East Boston envelope support.”

USPS chat agents are available Monday–Saturday, 7:00 AM–10:00 PM ET. They can:

• Verify your envelope size against USPS standards
• Provide a printable dimensional compliance checklist
• Generate a return label if your envelope was rejected
• Connect you to the East Boston regional team for escalation

Chat transcripts are saved and can be emailed to you for record-keeping — useful for businesses auditing their shipping compliance.

3. Email Support

For non-urgent issues, you can email USPS at customercare@usps.gov. Use the subject line: “Padded Flat Rate Envelope Dimension Inquiry – East Boston Region.”

Include:

• Your full name and contact information
• Envelope dimensions (length x width x thickness)
• Tracking number (if applicable)
• Photograph of the envelope (if damaged or mislabeled)

Response time: 1–3 business days. This method is best for documentation purposes or when you need a written record.

4. In-Person Support at East Boston Post Office

If you’re located near the East Boston Processing Center, you can visit the official USPS retail location at:

East Boston Post Office

300 Bennington Street

East Boston, MA 02128

Phone: 1-833-442-1712 (same as regional line)

Hours: Monday–Friday: 8:00 AM–6:00 PM | Saturday: 9:00 AM–5:00 PM | Sunday: Closed

Bring your envelope, shipping label, and any documentation. The staff can measure your envelope on-site using calibrated tools and provide immediate feedback on compliance.

5. USPS Mobile App

Download the official USPS Mobile App (available on iOS and Android). Under “Tools,” select “Packaging & Supplies.” Search “Padded Flat Rate Envelope.”

The app includes:

• Interactive dimension checker (drag and resize your envelope)
• Real-time pricing based on your ZIP code
• Direct link to East Boston regional support
• Barcode scanner to verify envelope ID

This is the fastest way for mobile users to verify compliance before heading to the post office.

6. Social Media Support

USPS actively monitors its official social media accounts for customer inquiries:

• Twitter: @USPSHelp
• Facebook: facebook.com/USPS
• Instagram: @usps

Send a direct message with your inquiry and include “East Boston” and “Padded Flat Rate Envelope” in your message. Response time is typically under 24 hours.

Worldwide Helpline Directory for USPS Padded Flat Rate Envelope Support

While the USPS Padded Flat Rate Envelope is designed for domestic U.S. shipping, many international businesses and expatriates use it to send items to the United States. If you’re located outside the U.S. and need support regarding the envelope’s dimensions, international shipping rules, or customs compliance, here is a global directory of official USPS support channels:

North America

• United States: 1-800-275-8777 | 1-833-442-1712 (East Boston)
• Canada: 1-800-465-8777 (USPS Canada Partnership Line)
• Mexico: 01-800-788-4477 (USPS-Mexico International Support)

Europe

• United Kingdom: 0800-783-2323 (USPS UK Partner)
• Germany: 0800-183-2323
• France: 0800-910-012
• Italy: 800-987-456

Asia-Pacific

• Australia: 1800-033-318
• Japan: 0120-111-245
• India: 1800-120-7244
• Singapore: 800-183-2323
• South Korea: 080-820-1122

Latin America

• Brazil: 0800-765-4321
• Argentina: 0800-555-2222
• Chile: 800-112-333

Africa and Middle East

• South Africa: 0800-001-234
• United Arab Emirates: 800-011-2233
• Saudi Arabia: 800-855-0100

Important: These international numbers are operated by USPS-approved partners and may have different hours. Always check the official USPS website for updated contact details. Do not use third-party agencies claiming to offer “USPS international support” — they are often scams.

For international customers: The Padded Flat Rate Envelope cannot be used for outbound international shipping from the U.S. — it is only for domestic use. If you’re shipping TO the U.S. from abroad, you must use your country’s postal service and select the equivalent of a USPS Flat Rate Envelope. The dimensions may vary slightly by country.

About USPS East Boston Padded Flat Rate Envelope Size Number – Dimension: Key Industries and Achievements

The USPS East Boston Padded Flat Rate Envelope has become a cornerstone of logistics for several key industries. Its standardized size, durability, and flat-rate pricing have made it indispensable for businesses seeking reliable, affordable shipping solutions.

1. E-Commerce and Retail

Small and medium-sized e-commerce businesses are the largest users of the Padded Flat Rate Envelope. Items such as clothing, accessories, books, and small electronics are shipped daily from fulfillment centers in the Boston area using this envelope. According to a 2023 USPS internal report, over 12 million Padded Flat Rate Envelopes were processed through East Boston alone — accounting for 18% of all flat rate envelope usage in the Northeast.

Major retailers like Etsy sellers, local Boston boutiques, and online bookstores rely on the envelope’s predictable $8.95 price (as of 2024) to maintain profit margins. The envelope’s padded lining reduces returns due to damaged goods — a critical factor for customer retention.

2. Healthcare and Medical Services

Hospitals, clinics, and labs in Massachusetts use the Padded Flat Rate Envelope to ship non-hazardous medical records, lab reports, prescriptions, and diagnostic samples. The envelope’s tamper-evident seal and cushioned design meet HIPAA-compliant shipping standards for non-sensitive data. The East Boston center has partnered with Boston Medical Center and Tufts Medical Center to provide pre-addressed, branded envelopes for patient records — reducing delivery times by 40%.

3. Education and Publishing

Universities and publishing houses in New England use the envelope to ship textbooks, student portfolios, and manuscripts. The envelope’s size is ideal for standard 8.5” x 11” paper documents. The East Boston facility offers discounted bulk rates to academic institutions, with over 200,000 envelopes shipped annually to Harvard, MIT, and Boston University.

4. Nonprofits and Religious Organizations

Charities and faith-based organizations use the envelope for donation receipts, newsletters, and fundraising materials. The USPS offers nonprofit rates for eligible organizations, and the Padded Flat Rate Envelope is often the most cost-effective option for bulk mailings.

Achievements and Recognition

• 2022: East Boston Processing Center awarded “Best Regional Logistics Hub” by the National Postal Council for reducing envelope misclassification errors by 67%.
• 2023: Launched “Envelope Compliance Guarantee” — if your envelope is rejected due to incorrect dimensions, USPS will re-ship it free of charge.
• 2024: Implemented AI-powered dimensional scanning at East Boston — 99.8% accuracy rate in envelope size verification.

These achievements underscore the center’s commitment to accuracy and customer satisfaction — making it one of the most trusted USPS facilities in the country.

Global Service Access

While the Padded Flat Rate Envelope is a U.S.-only product, its impact extends globally. International customers frequently ship items TO the United States using this envelope — but only if the item is sent via a U.S.-based sender. For example, an American living in Germany can use the envelope to send a gift to their family in Boston — but a German resident cannot use the envelope to send something to Boston unless they purchase it from a U.S. post office.

USPS offers global access to its packaging standards through:

• USPS Global Shipping Program (GSP): Allows international sellers to ship to the U.S. using local postal services, then hand off to USPS for final delivery. The Padded Flat Rate Envelope can be used for the U.S. leg of the journey.
• International Postal Partnerships: USPS collaborates with postal services in over 190 countries to align packaging standards. Many countries now offer “equivalent padded envelopes” with similar dimensions and pricing.
• Online Packaging Guides: The USPS website provides downloadable PDFs of envelope dimensions in 12 languages, helping international shippers verify compliance before purchasing.

For businesses shipping internationally, the key is to use the Padded Flat Rate Envelope only within the U.S. For outbound international shipping, use USPS Priority Mail International or Global Express Guaranteed — these services offer similar flat-rate pricing and global tracking.

FAQs

What is the exact size of the USPS East Boston Padded Flat Rate Envelope?

The USPS Padded Flat Rate Envelope measures 12-1/2 inches by 9-1/2 inches when flat. When sealed, it has a maximum thickness of 3/4 inch. The “East Boston” label does not change the size — it refers to the processing center, not the envelope itself.

Is there a different size for East Boston?

No. All USPS Padded Flat Rate Envelopes are standardized nationwide. There is no “East Boston version.” The term is often used in search queries by local customers seeking regional support.

What is the toll-free number for East Boston envelope support?

Call 1-833-442-1712 for specialized assistance with envelope dimensions, compliance, and East Boston processing issues.

Can I use this envelope to ship internationally?

No. The Padded Flat Rate Envelope is only for domestic U.S. shipments. For international shipping, use USPS Priority Mail International.

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

Measure the length, width, and thickness. If it exceeds 12-1/2” x 9-1/2” or 3/4” thickness, it will be charged at retail rates. Use the USPS app or visit a post office for verification.

What if my envelope was rejected at East Boston?

Contact 1-833-442-1712 or visit the East Boston Post Office at 300 Bennington Street. You may be eligible for a free re-shipment under the “Envelope Compliance Guarantee.”

Can I buy these envelopes online?

Yes. Visit www.usps.com/shop and search “Padded Flat Rate Envelope.” Free delivery is available to all U.S. addresses.

Do I need to use a specific label?

No. Use any USPS Priority Mail label. The envelope itself is pre-paid for flat rate shipping. Just ensure the label says “Priority Mail Flat Rate.”

What’s the cost to ship one envelope?

As of 2024, the cost is $8.95 for commercial base pricing and $9.65 at the post office counter. Prices are subject to change — always check USPS.gov for current rates.

How long does delivery take?

1–3 business days for most U.S. destinations. East Boston shipments to other Northeast states often arrive in 1 day.

Conclusion

The USPS Padded Flat Rate Envelope is a simple yet powerful tool that has revolutionized how Americans ship lightweight, protected items. While its dimensions are standardized nationwide, the East Boston Processing Center stands out as a critical hub for high-volume, high-accuracy shipping operations — especially in the Northeast. Whether you’re a small business owner, an online seller, or an individual sending a thoughtful gift, understanding the exact size, official number, and how to access specialized support can make all the difference in your shipping experience.

Remember: The envelope’s size is 12-1/2” x 9-1/2” x 3/4”. The official toll-free number for East Boston-specific envelope inquiries is 1-833-442-1712. Use the USPS app to verify dimensions before shipping. For international customers, the envelope is only usable within the United States — but global shipping partners offer equivalent solutions.

By leveraging the resources outlined in this guide — from live chat to regional helplines to in-person support — you can avoid costly mistakes, reduce delivery delays, and ensure your items arrive safely and affordably. The USPS East Boston Padded Flat Rate Envelope isn’t just a box or envelope — it’s a trusted link in the chain of American commerce. Use it wisely, and support it correctly.