Flat mailers sizes and

Flat mailers, also known as flat rate boxes or envelopes, are a convenient and cost-effective way to ship items of a standard size and weight. Here are some common sizes and dimensions for flat mailers:

USPS Flat Rate Envelopes:

• Small Flat Rate Envelope: 5-1/2" x 8-1/2" x 0.007" (13.97 cm x 21.59 cm x 0.18 mm)
• Medium Flat Rate Envelope: 9-1/2" x 11-5/8" x 0.0125" (24.13 cm x 29.53 cm x 0.32 mm)
• Large Flat Rate Envelope: 12-1/4" x 15-1/2" x 0.018" (31.12 cm x 39.37 cm x 0.46 mm)

USPS Flat Rate Boxes:

• Small Flat Rate Box: 5-1/2" x 8-1/2" x 1-1/2" (13.97 cm x 21.59 cm x 3.81 cm)
• Medium Flat Rate Box: 11" x 13-1/2" x 2" (27.94 cm x 34.29 cm x 5.08 cm)
• Large Flat Rate Box: 12" x 12" x 5-1/2" (30.48 cm x 30.48 cm x 13.97 cm)
• Extra Large Flat Rate Box: 12-1/4" x 12-1/4" x 3" (31.12 cm x 31.12 cm x 7.62 cm)

UPS Flat Rate Envelopes:

• Small Flat Rate Envelope: 6" x 9" x 0.012" (15.24 cm x 22.86 cm x 0.30 mm)
• Medium Flat Rate Envelope: 9" x 12" x 0.015" (22.86 cm x 30.48 cm x 0.38 mm)
• Large Flat Rate Envelope: 12" x 15" x 0.018" (30.48 cm x 38.1 cm x 0.46 mm)

FedEx Flat Rate Envelopes:

• Small Flat Rate Envelope: 6" x 9" x 0.012" (15.24 cm x 22.86 cm x 0.30 mm)
• Medium Flat Rate Envelope: 9" x 12" x 0.015" (22.86 cm x 30.48 cm x 0.38 mm)
• Large Flat Rate Envelope: 12" x 15" x 0.018" (30.48 cm x 38.1 cm x 0.46 mm)

Please note that these sizes and dimensions are subject to change, and it's always best to check with the shipping carrier for the most up-to-date information.