USPS flat rate box sizes and prices are key to smart shipping. Whether you sell online, run a small business, or send gifts, knowing flat rate boxes helps save time and money. In this guide, you’ll learn about all box types, when to use them, and how to save on shipping costs.

In the next part, you’ll see detailed info on usps boxes sizes and prices so you can choose the best box for your items. We’ll also show you how Your Box Packaging supports safe and smart shipping.

Why Flat Rate Boxes Are Helpful

Flat rate boxes let you ship items anywhere in the U.S. for one set fee no matter weight. This is great if you ship heavy products that cost a lot by weight. Flat rate options make shipping easy and predictable.

Flat Rate Is Simple and Fast

All flat rate boxes and envelopes ship for the same price based on their type. You don’t need to weigh each package. This helps you plan shipping costs quickly, even for heavy snacks, books, or items.

USPS Flat Rate Box Types

USPS offers many flat rate boxes and envelopes. Here are the main sizes:

Flat Rate Envelopes

• Letter (9-1/2″ x 4-1/4″)

• Legal (15″ x 9-1/2″)

• Padded (9-1/2″ x 12-1/2″)

Flat Rate Boxes

Small Box:

8-5/8″ x 5-3/8″ x 1-5/8″

Medium Boxes (Two Types):

• 11″ x 8-1/2″ x 5-1/2″

• 13-5/8″ x 11-7/8″ x 3-3/8″

Large Box:

12-1/4″ x 12-1/4″ x 6″

APO/FPO Large Box:

12-1/4″ x 12-1/4″ x 6″

Regional Rate Boxes

• A Series: 10″ x 7″ x 4-3/4″

• B Series: 12″ x 10-1/4″ x 5-1/4″

Understanding USPS Flat Rate Prices

Flat rate prices change from time to time. Here are current 2025 USPS rates:

• Envelope: $9.65

• Small Box: $10.40

• Medium A: $17.10

• Medium B: $17.10

• Large Box: $22.80

• APO/FPO Large: $22.80

• Regional A: $17.20

• Regional B: $24.10

These rates apply to domestic shipping. Hawaii and Alaska use the same rate for most zones.

Weight and Size Limits

Flat rate boxes allow up to 70 lb. However, oversized items that don’t fit box size rules may get extra charges.

Size Rules

You must use official USPS flat rate boxes and envelopes. Homemade containers may be charged at regular rates.

Choosing the Right Box: Key Tips

• Small box: good for jewelry, small electronics, or USB drives

• Flat rate envelope: ideal for documents, photos, or thin items

• Medium box: fits shoes, clothes, mid-size products

• Large box: best for bulk or multiple items

• Regional boxes: save when shipping to nearby states

Comparing Flat Rate to Weight-Based Shipping

Weight-based rates use size and weight, which can be cheaper for light items. Flat rate is better when your package is heavy or bulky but fits its box. see more

Preparing Your Package

Packing Steps:

• Clean place to pack

• Bubble wrap when needed

• Fill space with paper or packing peanuts

• Close the box securely with tape

Labeling Tips:

• Print flat rate label from USPS or handwrite legibly

• Track your package online for delivery updates

Special Flat Rate Options

• APO/FPO Flat Rate Box: for military mail overseas

• Regional Rate: cheaper when shipping to nearby zones

• Flat Rate Padded Envelope: protects fragile items

Using Flat Rate for Business

E-commerce sellers and small business owners find flat rate boxes helpful. They simplify shipping and provide reliable pricing, which enhances customer trust.

Money-Saving Strategies

• Buy flat rate boxes in bulk

• Use regional boxes when shipping close by

• Weigh items first to see if flat rate is cheaper

• Reuse flat rate boxes when allowed

Tracking and Insurance

USPS flat rate includes tracking and limited insurance ($100 for domestic Priority Mail). You can buy extra insurance for valuable items.

International Flat Rate

You can ship internationally using Priority Mail Flat Rate. It takes 6–10 days to deliver. For items over 4 lb, check Global Express documents.

Flat Rate for Heavy and Bulk Items

Flat rate boxes are ideal for shipping dense or heavy items. Just ensure your packaging holds up and fits in box dimensions.

Gift Shipping Using Flat Rate

Flat rate boxes are fun for sending gifts during holidays. Regional boxes help save costs for nearby deliveries.

Custom Packaging with Branding

Many shops brand their flat rate boxes with custom tape, stickers, or sleeves. Unique designs help your items stand out in transit.

Common Questions Answered

Q: Can I reuse flat rate boxes?
A: Yes, but tape old labels and remove old markings.

Q: What if I combine two flats?
A: If you pack medium inside large, you pay extra.

Q: International shipping allowed?
A: Yes, for Priority Mail International Flat Rate.

Environmental Focus

Empty your box, remove tape, flatten it, and recycle.Your Box Packaging Use eco-friendly cushioning like paper. Better materials help protect the planet.

Final Package Planning Guide

Here is a checklist when shipping with flat rate:

• Measure items and choose correct box

• Compare flat rate vs weight-based options

• Use correct boxes and seals

• Photo your package before shipping

• Keep tracking number for monitoring

Free Tools and Online Estimates

USPS has a calculator for rates. Online tools help you compare quickly. You can also schedule pickups in advance.

Flat Rate for Small Businesses vs Individuals

Both benefit from flat rate boxes. Businesses get bulk discounts. Individuals get easy and predictable costs. It works for everyone.

Future Trends

USPS is looking at new sizes and smart features like digital stamps. They may add new eco-friendly box options soon.

Summary and Final Thoughts

Flat rate boxes are simple, reliable, and cost-effective for shipping. Now you know all about usps boxes sizes and prices from official rates to smart packing tips. For customized packaging that boosts your brand and keeps your items safe, trust Your Box Packaging they help you find the perfect box for your business needs.