Postal Explorer

The Postal Service is reminding customers that metallic mercury and devices containing metallic mercury are always prohibited in the mail stream. This includes antique items such as thermometers, barometers, blood pressure monitors and similar devices.

201c Quick Service Guide

Physical Standards for Commercial Flats

Overview

Flat Dimensions
		Minimum*	Maximum
	Length	11-1/2 inches	15 inches
	Height	6-1/8 inches	12 inches
	Thickness	1/4 inch	3/4 inch
	* Flats exceed at least one of these dimensions

For physical standards of automation flats, see Quick Service Guide 201d.

In addition to shape, the Postal Service classifies mailpieces by the way they are prepared. These classifications are based on how efficiently your mailpieces can be processed on Postal Service equipment. The Postal Service classifies commercial flats as either nonautomation or automation flats or machinable and nonmachinable for Periodicals.

A flat meets automation standards and qualifies for automation prices if it meets the specific addressing, barcoding, and design standards. Automation flats must have a POSTNET or Intelligent Mail barcode with a delivery point routing code.

Dimensions, Shape, Flexibility, and Uniform Thickness (201.4.0)

Dimensions:

Minimum: more than 11-1/2 inches long, or more than 6-1/8 inches high, or more than 1/4 inch thick.
Maximum: 15 inches long, 12 inches high, and 3/4 inch thick.

The length of a flat-size mailpiece is the longest dimension. The height is the dimension perpendicular to the length.

Shape: rectangular, with four square corners, or with finished corners that do not exceed a radius of 0.125 inch (1/8 inch).

Flexibility and deflection: flat-size pieces must meet flexibility criteria in 201.4.3 and the deflection criteria in 201.4.6. Flat-size pieces mailed at high density, high density plus, saturation, and basic carrier route prices are not required to meet deflection standards. All other flats not meeting deflection standards are subject to prices as stated in DMM 201.4.7.

Uniform thickness: the contents must be uniformly thick so that any bumps, protrusions, or irregularities do not cause more than 1/4 inch variance in thickness (201.4.4). When determining variance in thickness, exclude the outer edges of a mailpiece (1 inch from each edge) when the contents do not extend to the edges.

Mailpieces that do not meet the standards for flexibility in 201.4.3, for uniform thickness in 201.4.4, or for polywrap in 201.4.5, must pay applicable prices as follows: