USPS USPS Flat Rate Boxes & Pricing

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What are USPS Flat Rate Boxes?

USPS Flat Rate Boxes are just that - boxes with flat postage rates, no matter how heavy the package is. If you're shipping heavy, small items, Flat Rate Boxes are the best bang-for-your-buck option. Take advantage of USPS flat rates by keeping a supply of these around your fulfillment operations. Using a USPS Flat Rate Box can cut your shipping costs by 50%. This is a great way to prepare for peak shipping.

In addition to large Flat Rate Boxes, small Flat Rate Boxes and medium Flat Rate Box prices are supported through the EasyPost API by using our predefined packages. So it's easy to set up internally and start collecting savings from your Flat Rate Boxes as soon as you integrate with EasyPost.

How Much Do USPS Flat Rate Boxes Cost?

We've broken the pricing into the table below. Note: The rates below reflect USPS Commercial Plus Pricing, which is available when shipping via EasyPost. If you're interested in signing up for USPS Commercial Plus Pricing, contact us and we can set you up.

USPS Priority Mail Flat Rate Options

Last Updated: January 24, 2021.

TypeSizeEasyPost Predefined PackagePrice
Letter Envelope12 1/2" x 9 1/2"FlatRateEnvelope$7.40
Gift Card Envelopes10" x 7"FlatRateGiftCardEnvelope$7.40
Window Envelopes10" x 6"FlatRateWindowEnvelope$7.40
Small Envelopes10" x 6"SmallFlatRateEnvelope$7.55
Padded Envelopes12 1/2" x 9 1/2"FlatRatePaddedEnvelope$8.00
Legal Envelopes15" x 9 1/2"FlatRateLegalEnvelope$7.70
Small Box8 11/16" x 5 7/16" x 1 3/4"SmallFlatRateBox$7.90
Medium Boxes11 1/4" x 8 3/4" x 6" or 14" x 12" x 3 1/2"MediumFlatRateBox$13.75
Large Box12-1/4" x 12-1/4" x 6" or 24-1/16" x 11-7/8" x 3-1/8"LargeFlatRateBox$19.30
APO/FPO Box12-1/4" x 12-1/4" x 6"LargeFlatRateBoxAPOFPO$17.80

Note: Rates are ESTIMATED. When you purchase postage, these rates may differ.

If you have any questions about our Commercial Plus pricing use the button below to contact us.

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