Is it cheaper to use your own box or a priority Mail box?

When shipping packages, one of the first decisions you need to make is what type of box or packaging to use. You basically have two options – use your own box that you provide or use a box provided by the shipping carrier, such as a Priority Mail box from the United States Postal Service (USPS). There are pros and cons to each approach and the cheaper option depends on several factors. We’ll look at the key considerations in deciding whether it is more cost effective for you to supply your own box versus using a Priority Mail box.

What is a Priority Mail box?

A Priority Mail box is a shipping box provided by the USPS for sending packages using their Priority Mail service. Priority Mail is a 1-3 day delivery service for packages and envelopes up to 70 pounds. The USPS offers free Priority Mail boxes in a variety of sizes, including flat rate boxes.

Flat rate boxes are a special type of Priority Mail box where the postage is based on the box size, regardless of weight or destination (as long as within the US). This means you pay the same price to ship a 5 lb package as you would a 25 lb package in the same flat rate box. Common flat rate box sizes include Small, Medium, Large, and various Regional Rate boxes.

Using a Priority Mail box comes with several potential advantages:

  • Boxes are free – no need to purchase packaging
  • Specific flat rate pricing regardless of package weight
  • Tracking and insurance may be included
  • 1-3 day delivery

However, there are also some potential disadvantages:

  • Boxes only come in set sizes – may not fit item optimally
  • Flat rate prioritizes speed over cost efficiency
  • Packing materials not included

What are the pros of using your own box?

Providing your own box allows for some key benefits:

Better fit

You can select a box that fits the dimensions of your items as tightly as possible. This prevents excess empty space and materials. Getting a close fit helps limit box size to the minimum needed for adequate protection.


You can choose a sturdy box constructed from thicker, higher-grade corrugated cardboard or double-walled. This provides maximum protection for fragile items.

Custom design

A custom box can be designed specifically for odd-shaped items using inserts, dividers, and custom cutting and folding. You can create exactly what you need.


Use custom printed boxes featuring your logo, brand colors and messaging. Turn packaging into a marketing tool.

Less waste

Ordering custom box sizes in bulk quantities generates less waste. Only what you need is produced versus relying on a carrier’s standard sizes.

Lower cost

For lighter packages, dimensional weight pricing results in lower shipping costs when tightly fitting the exact box size needed versus using a larger standard box.

What are the cons of using your own box?

While supplying your own packaging allows for maximum flexibility and efficiency, there are also some potential disadvantages:

Upfront cost

Unless you already have extra boxes on hand, you’ll need to cover the upfront cost of purchasing custom packaging. For one-time or infrequent shipments, this may be more expensive than using free Priority Mail boxes.

Labor for packing

It takes extra staff time to select appropriate packaging and properly pack items. Priority Mail boxes can be quicker by eliminating this step.

Storage space

You need room to store blank boxes. Storing a variety of box sizes to accommodate different items takes up warehouse space.

No built-in tracking/insurance

You’d need to purchase delivery confirmation, tracking, and insurance separately when using your own box. Priority Mail includes these services.

No priority handling

Using your own box means shipping via standard ground services. Priority Mail gets expedited handling.

What are the pros of using a Priority Mail box?

There are several potential benefits to using USPS provided Priority Mail boxes:

Free boxes

You don’t pay anything for the actual box itself. This eliminates the upfront cost of purchasing packaging.

Fast shipping

Priority Mail boxes come with expedited 1-3 day delivery timeframes. Your package gets priority handling versus standard ground.

Flat rate pricing

If using a Priority Mail flat rate box, the same postage rate applies regardless of package weight or destination. Simplified flat rate pricing can sometimes result in discounts.

Tracking and insurance

Get up to $50 of included insurance on Priority Mail shipments. Tracking also comes standard at no extra cost.

Free packaging supplies

Priority Mail boxes also come with free tape and labels. All you need to pack and ship is bundled together.

Wide availability

Order boxes for free on or pick them up at any post office location. Priority Mail boxes are widely accessible and convenient.

What are the cons of using a Priority Mail box?

However, there are also some drawbacks to relying on Priority Mail boxes:

Limited box sizes

You can only choose from the set box sizes offered by USPS. If none fit your item snugly, you’ll end up overpaying for excess space.

Non-custom packaging

Since Priority Mail boxes are standard, you lose the branding and design options of custom printed boxes.

No protection options

Priority Mail boxes provide minimal padding. You need to supply your own protective wrapping and inserts.

Heavy items cost more

On non flat rate Priority Mail, heavy items lose cost efficiency versus lighter packages. Dimensional weight drives cost for heavy items.

Regional rate differences

Regional rate boxes have lower postage only for certain zones. Outside those zones, normal Priority Mail rates apply.

Does weight or distance impact cost?

Both package weight and shipping distance heavily influence the final shipping costs. This affects whether your own box or a Priority Mail box will be cheaper.

Package weight

On normal Priority Mail, heavier packages cost more to ship. Each additional pound drives up the price due to dimensional weight. With your own packaging you can sometimes size a lighter box to save money.

Shipping distance

Zone based pricing means shipments going longer distances typically cost more. Regional rate Priority Mail boxes offer discounts, but only for packages traveling shorter zones. Your own box avoids zone pricing issues.

Dimensional weight

If a package measures larger than one cubic foot (1 lb./cu. ft.), dimensional weight pricing is applied. This bases cost on package volume not just weight. A smaller custom box can avoid dimensional pricing.

Flat rate advantage

With Priority Mail flat rate boxes, the same price applies regardless of weight or distance. Heavier, longer distance packages benefit most from flat rate savings.

Does package content make a difference?

The contents of your package can also impact costs and guide the best box choice:

Fragile items

For breakable items needing lots of protection, a thicker custom box means less damage risk.

Irregular shapes

Odd sized or shaped contents like golf clubs do better in a fitted custom box versus rattling around a large Priority Mail box.

Dense vs. light

Light but bulky items like clothing can take up space without much actual weight. Your own compact box saves money.

Valuable contents

If package value exceeds $50, pay extra for full insurance coverage using your own box.


Special packaging like reinforced boxes and absorbent materials may be required, necessitating a custom approach.

How much does each type of box cost?

Below are typical costs for common box types and sizes:

Priority Mail flat rate boxes

  • Small – $9.45
  • Medium – $16.10
  • Large – $21.50
  • Large APO/FPO/DPO – $20.95
  • Regular envelope – $8.45
  • Legal envelope – $9.65
  • Padded envelope – $8.55

Priority Mail regional rate boxes

  • A – $8.40
  • B – $9.65
  • Regional rate box – $10.40

Custom box costs

  • Small box (<1 cubic foot) - ~$1
  • Medium box (1-3 cubic feet) – ~$2
  • Large box (3-5 cubic feet) – ~$3
  • Corrugated cardboard – $0.50-$0.70 per square foot
  • Kraft paper cushioning – $0.20 per square foot
  • Tissue paper cushioning – $0.10 per sheet

As you can see, Priority Mail flat rate postage stays the same regardless of box size. With custom boxes, larger sizes cost a bit more but remain fairly affordable.

What are the postage rates?

Postage rates also factor into the total cost comparison:

Priority Mail rates

  • Zones 1-4 – starting at $8.40
  • Zones 5-9 – starting at $9.85
  • Plus $0.60 per additional pound

Standard ground shipping

  • Zones 1-4 – starting at $8.80
  • Zones 5-9 – starting at $10.60
  • Plus $0.65 per additional pound

Dimensional weight pricing

  • Zones 1-2 – $19.65 for 1-70 lbs.
  • Zones 3-9 – $25.60 for 1-70 lbs.

Ground shipping is slightly cheaper than Priority Mail for lighter packages. But Priority Mail flat rates can save significantly on heavier contents.

How can you optimize costs with your own box?

If using your own boxes, there are ways to optimize packaging and minimize shipping costs:

Get an exact fit

Measure items and order boxes tailored specifically. Eliminate empty space inside.

Under 1 cubic foot

Keep package volume small to avoid dimensional weight. Costs jump for over 1 cubic foot.

Lightweight materials

Use light but sturdy materials like corrugated cardboard to minimize weight.

Multi-pack discounts

Buy boxes in bulk for lower per unit costs. Can be 50%+ savings.

Zone skipping

Determine best origin/destination pairing to skip zones. Keeps ground rates low.

Cubic pricing

Cubic pricing bases cost purely on volume. Can yield significant savings.

How can you optimize costs with a Priority Mail box?

Using free Priority Mail boxes can also be cost effective if following certain tips:

Flat rate for heavy items

The flat rate avoids dim weight jump for heavier contents regardless of distance.

Package consolidation

Consolidate multiple lighter items into one larger flat rate box.

Regional rate for short zones

Regional rate boxes offer discounts for shorter zone packages.

Flat rate envelopes

Use flat rate envelopes for documents, small parts, and lightweight items.

Padded vs. regular

Padded flat rate costs slightly more but includes $50 of insurance already.

Flat rate stickers

Apply flat rate stickers to any qualifying box to get the flat rate price.

Can you combine USPS shipping services?

Certain USPS shipping services can be combined together to maximize efficiency and cost savings:

USPS pick-up

Schedule USPS pick-up from your location to save trips to the post office.

USPS insurance

Add extra insurance beyond the included $50 coverage on Priority Mail.

Signature confirmation

Get delivery signature proof and avoid lost package claims.

Scheduled delivery

Have packages delivered on specific dates if needed for coordination.

USPS Tracking

Free tracking provides visibility into shipment status and delivery.

Consolidated labels

Print multiple packages on one label through USPS Click-N-Ship.

USPS loyalty programs

Participate in small business and volume shipping discounts and rewards.

Should you use your own box or Priority Mail?

Consider the following factors when deciding which type of packaging to use for your mail and packages:

Package weight

Heavier packages typically get better pricing in a Priority Mail flat rate box.

Shipping distance

Longer distances make Priority Mail faster and more cost efficient.

Package dimensions

Odd or irregular shapes and sizes fit better in a custom box.

Item value

Valuable or fragile contents justify a sturdy custom box.

Frequency of shipping

Regular shipments merit investing in branded custom packaging.

Available time

Priority Mail boxes are quicker for one-off shipments on short notice.


There is no universal answer to whether supplying your own box or using a Priority Mail box is cheaper overall. The right choice depends on factors like package weight, shipping distance, delivery speed needed, value of contents and customization required.

Lightweight, short distance packages are often most affordable using your own pre-purchased boxes with zone-based ground shipping. Heavier, longer distance packages tend to get better rates in flat rate Priority Mail boxes.

Irregular or fragile contents also benefit from custom packaging. Evaluate each of your common shipping scenarios. Determine the optimal box choice and postage mix for those cases. With the right analysis and preparation, you can maximize savings on packaging and shipping.

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