Postage Without Additional-Ounce Stamps

Copyright © 2024 by David Wincelberg

The postage rate for mailing a regular first-class letter in the United States starting is $ for the first ounce and $ for additional ounces up to 3.5 ounces. After that, you must use the rate for large envelopes, called flats, which starts at $ and also adds $ for additional ounces.

Note: The USPS table for flats does not match this pattern. There might be an error on their part.

Suppose that you only have -cent stamps. What should you do? You could affix one such stamp for each ounce. However, two first-ounce stamps covers three ounces for a letter. The first table shows the costs for up to 3.5 ounces for letters and the number of first-ounce stamps needed when you don't have additional-ounce stamps. The second table does the same for large envelopes. (Stamped items over 10 ounces or 1/2-inch thick must be presented at a post-office counter.) The third table shows the values when only first-ounce stamps are applied and how many ounces for letters and flats are covered by using only these stamps.

Oz Letter
Rates
Stamps
Needed
Excess
1
2
3
3.5

Oz Flat
Rates
Stamps
Needed
Excess
1
2
3
4
5
6
7
8
9
10
11
12
13

Stamps Cost Covers
Letters
Covers
Flats

Following are the size requirements in inches for letters and large envelopes (flats). If any of the limits on flats are exceeded, then package rates apply. If any of the limits on letters are exceeded without exceeding the corresponding limit for flats, then the rates for flats apply. The minimum requirements must be met for both letters and flats.

Dimension Min
Max
Letters
Max
Flats
Length
(side to side)
5 11 1/2 15
Height
(top to bottom)
3 1/2 6 1/8 12
Thickness
(front to back)
0.007 1/4 3/4

References

  1. USPS Postal Explorer: First-Class Mail
  2. USPS Postal Explorer: Quick Reference—Domestic
  3. USPS Postage Rates—Stamps.com

Disclaimer: The above information is based on that from USPS.com. Although intended to be accurate, errors may occur. You assume all risks in using the information on this page.


Contact

david.wincelberg@gmail.com

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Last updated: 14-July-2024