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Product Count Estimates for USPS Flat Rate Boxes

03 Apr, 2016

US Postal Service Priority Mail Flat Rate Shipping Options

Here is a brief list of some of our most popular items that fit into USPS Flat Rate boxes:

Estimated* Quantities Eligible for Shipment in USPS Flat Rate Boxes

Product Medium
Flat Rate
Flat Rate
Mountain House Pro-Pak Pouch 4-7 8-10
Mountain House Adventure Meal Pouch 4-7 8-10
Peak Refuel Entrees & Desserts 4-7 8-10
MRE Entrees 12-19 19-27
MRE Side Dishes 19-21 21-27
MRE Sandwiches & Turnovers 18-21 22-30
MRE Sandwich Wraps 20-24 25-40

US Postal Service Flat Rate Box Sizes (Dimensions)

If an item or items(s) are too large to fit into a USPS Flat Rate Box or if a lower shipping method cost is available, the Flat Rate Box shipping option will not be displayed.

  • USPS Small Flat Rate Box
    8-5/8" x 5-3/8" x 1-5/8"
  • USPS Medium Flat Rate Box
    11" x 8-1/2" x 5"
  • USPS Large Flat Rate Box
    12" x 12" x 5-1/2"
  • USPS Priority & USPS Ground Advantage (Zone, Weight, Volume & Dimensional Based Weights)
    We will ship in the best-fit box sizes for non-flat rate USPS available shipping methods.

Note: Some items are not eligible to ship via USPS or UPS due to Post Office Rules and FAA Regulations. Examples of items ineligible to ship include MRE Flameless Ration Heaters, Fuel & Fuel Gels, Matches, etc.

Disclaimer: These are ESTIMATED* quantities only; items can change packaging dimensions at any time without prior notice which can change the maximum product quantities that can fit inside any particular flat rate box at any given time.