What Size Boxes Does Usps Have?

USPS offers free Priority Mail Flat Rate boxes in Small (8-11/16" x 5-7/16" x 1-3/4"), Medium (11-1/4" x 8-3/4" x 6" or 14-1/8" x 12" x 3-1/2"), and Large (12-1/4" x 12" x 6"), all up to 70 lbs. You’ll also find specialty sizes: tubes for posters, a shoe box, side-loading large boxes, and cremated remains kits. Military APO/FPO Flat Rate options are available. Prepaid Flat Rate boxes lock in pricing. Explore which box fits your shipment best.

Main Points

• USPS Priority Mail Flat Rate boxes: Small (8-11/16" x 5-7/16" x 1-3/4"), Medium (two sizes), and Large (12-1/4" x 12" x 6").
• Medium Flat Rate options: 11-1/4" x 8-3/4" x 6" or side-loading 14-1/8" x 12" x 3-1/2".
• Specialty boxes/tubes include a Dual-Use Small Tube (25-9/16" x 6" x 5-1/4") and a Shoe Box (14-7/8" x 5-1/4" x 7-3/8").
• Side-Loading Large Box for flat items measures 15" x 12" x 3-1/8"; free supplies available online.
• APO/FPO Flat Rate Box measures 12-1/4" x 12" x 6"; military care kits and bulk packs offered.

Priority Mail Service Features

Even if you’re shipping on a tight deadline, USPS Priority Mail delivers in 2–3 business days with end-to-end tracking and free pickup.

With Priority Mail service, you get USPS tracking, discounted rates, and delivery reliability for parcels up to 70 lbs. You can choose Flat Rate options or pay by weight and zone.

Enjoy USPS tracking, discounted rates, and reliable delivery up to 70 lbs—Flat Rate or by weight and zone.

You’ll access Free envelopes and Shipping supplies, including multiple Box sizes—like Medium Cube-Shaped—at no added cost.

Priority Mail®/Priority Mail Express branding makes it easy to distinguish speed tiers. Flat Rate simplifies pricing nationwide, while free materials streamline prep.

Order supplies online, pack, and hand off for swift, traceable delivery.

Flat Rate Box Sizes and Dimensions

When you need predictable pricing, USPS Priority Mail Flat Rate boxes come in clearly defined sizes with set dimensions.

You’ll choose from Flat Rate Boxes in Small, Medium, and Large to match your items and control costs.

Small measures 8-11/16" x 5-7/16" x 1-3/4". Medium measures 11-1/4" x 8-3/4" x 6", plus a Medium side-loading option at 14-1/8" x 12" x 3-1/2". Large measures 12-1/4" x 12" x 6".

With Priority Mail Flat Rate packaging, you can ship up to 70 lbs for one price nationwide—cost-effective shipping regardless of zone.

All boxes are free from USPS and orderable online in 10 or 25.

Specialty Boxes and Tubes

Flat Rate sizes cover most needs, but USPS also offers specialty boxes and tubes for items that don’t fit standard shapes.

You can choose Priority Mail Specialty Boxes by purpose and dimensions to protect contents and speed shipping.

Use the Dual-Use Priority Mail Small Tube Box (25-9/16 x 6 x 5-1/4) for posters and artwork.

Ship footwear in the Priority Mail Shoe Box (14-7/8 x 5-1/4 x 7-3/8).

Load prints or flat items with the Side-Loading Large Box (15 x 12 x 3-1/8).

For remains, select the Small Cremated Remains Kit (Kit 1 or 2, 9-5/8 x 7-3/4 x 6-1/4), meeting USPS requirements.

Avoid APO/FPO-specific boxes here.

Military and APO/FPO Box Options

Though most shipments fit standard Priority Mail, USPS also offers dedicated Military and APO/FPO options to streamline care packages to service members overseas.

You can use the Priority Mail Flat Rate APO/FPO Box, sized 12-1/4(L) x 12(W) x 6(H), for shipping to military personnel quickly and reliably. These military care package boxes are free to order, making them a cost-effective solution for shipping items to APO/FPO/DPO addresses.

1. APO/FPO Box: Flat Rate convenience with the 12-1/4 x 12 x 6 size.
2. Military Care Kit: Six boxes, tape, and labels to speed care packages.
3. Bulk ordering: Packs of 10 or 25 simplify sending multiple boxes.

Forever Prepaid Flat Rate Boxes and Pricing

If you’re sending frequent shipments—whether to service members or stateside—USPS Forever Prepaid Flat Rate Boxes keep costs predictable.

With Forever Prepaid Flat Rate prepaid boxes, you pay once and ship at a flat rate despite future increases. Choose a Small Box at $11.70, a Medium Box at $15.50, or a Large Box at $21.90; that’s the current pricing.

These are cost-effective for shipping packages regularly and include your return address. They don’t expire and must meet flat rate weight limits.

Select the size that fits your contents and budget, then pack, label, and ship with confidence knowing your cost won’t change.

Ordering, Quantities, and Availability

Two easy ways to get USPS boxes are online ordering and picking them up at your local Post Office, but availability varies.

Order USPS boxes online in packs of 10 or 25, with free delivery and reliable availability across sizes, including Flat Rate. Most boxes are free; Forever Prepaid Flat Rate boxes must be purchased.

Local Post Offices may have limited stock, so ordering guarantees specific quantities and types. You can return unused boxes to any Post Office. Track shipments of your box order using the USPS website and your receipt.

1. Choose quantities: 10 or 25.
2. Prioritize Flat Rate needs.
3. Use online ordering for availability and tracking.

Tips for Choosing the Right USPS Box Size

Before you pick a USPS box, match your item’s size and weight to the box that fits snugly with room for padding.

Check dimensions first: compare your item to Flat Rate boxes (Small, Medium, Large) and specialty options like the Priority Mail Shoe Box for a specific product.

If you need more volume, consider the Priority Mail Large Box to control shipping costs.

Use Flat Rate for packages up to 70 lbs when weight is high but size is modest.

For variable box sizes, price by zone and weight.

Lock in prepaid postage with Priority Mail Forever Prepaid to simplify budgeting.

Frequently Asked Questions

Is It Cheaper to Send a 20 Lb Box UPS or USPS?

Usually, USPS is cheaper for a 20 lb box, especially with Priority Mail Flat Rate.

You’ll pay fixed shipping costs up to USPS weight limits, while UPS varies by shipping zones and regional rates.

Compare delivery speed and service options: USPS includes tracking features and reasonable insurance rates; UPS can be faster for some lanes.

Consider packaging materials and customer service.

Use both calculators to verify the best price for your route and timeframe.

Does the USPS Have Free Boxes?

Yes, USPS offers free boxes. You can order free shipping supplies online, including Priority Mail and Flat Rate packaging options in multiple box sizes.

Most Priority Mail and Priority Mail Express postal services include boxes at no charge. You’ll get tracking shipments and reliable delivery times.

Start by ordering boxes in packs of 10 or 25, shipped free to you. These shipping supplies cover APO/FPO needs too, making your mailing straightforward and cost-effective.

Is It Cheaper to Use Your Own Box or a Priority Mail Box?

It depends. For heavier items, Priority Mail Flat Rate is usually cheaper because shipping costs ignore weight considerations and local rates.

For light, small items, your own box can win if box dimensions are compact.

Do a cost comparison: weigh the package, check delivery speed, insurance options, and packaging materials.

Flat Rate includes predictable pricing and often better value for dense shipments.

Compare Priority Mail calculators for both options before choosing.

How Much Does a Big Box Cost at USPS?

A big USPS Priority Mail Flat Rate Large Box costs $29.95. You can ship up to 70 lbs nationwide at one price, regardless of zone pricing, package dimensions, or delivery times.

If your box isn’t flat rate, shipping costs depend on weight limits, size, distance, and regional rates. You’ll get tracking services included and basic insurance options; buy more if needed.

For quotes or help, contact customer service or use the online calculator.