The rates are posted on the USPS web site. Square envelopes are charged a "non machinable surcharge" in addition to regular postage. That surcharge is 20 cents for any piece of first class mail as of August 2012. The non machinable criteria are outlined in the "Domestic Mailing Manual" in the "Physical standards" section. Letters need to have an aspect ratio between 1.3 and 2.5 to be considered machinable. The aspect ratio is the width divided by the height; square envelopes have an aspect ratio of 1, which is less than minimum 1.3 required. There are other conditions as well, but even if multiple criteria are met, only a single surcharge is charged.
Other than that, normal first class postage applies: 45 cents for the first ounce and 20 cents for each additional ounce up to 3.5 ounces. (as of August 2012)
If the dimensions cause it to be classified as a "large envelope" ot the weight exceeds 3.5 ounces, (smallest side > 6 1/8"), the "Large Envelope" rates apply.
An example:
I recently had to go to the post office to pick up two postage due items. One was 5x5 and one was 6 1/2 x 6 1/2. Each one had a normal 45 cent stamp on it. I had to pay 20 cents more for the 5x5 (because it exceeded the aspect ratio) and I had to pay 45 cents more for the larger one (to make up the difference in postage for a "Large Envelope"). Technically, the postage due should have been $0.65 for the 6 1/2 x 6 1/2, but since it was both large and nonmachinable, but I guess they let the surcharge slide.
an 8x8 envelope is charged "parcel rate"..because it is square and over the letter size dimension...cant be a "large envelope" because it is not rectangular
An envelope with a height exceeding 6 and one-eighths inches, and any square envelope, is non-machinable. Therefore, the rate for first class US domestic postage is $.64.
In the US, $1.56.
thirty-two cents
99 cents in a standard envelope.
Go to the site below and click on the "Calculate Postage" tab.
The cost is 98 cents for an ordinary one-ounce letter.
The current postage cost for a USPS First Class Mail Letter (1 oz. ) is $0.49. Unless, the letter's weight is more than 1 oz. it is not more than that.
postage fo 6.3 oz legal envelope
A regular envelope cost $1.89 to send to Mexico.
Square EnvelopesSquare envelopes are subject to the $0.20 nonmachinable surcharge.As of May 11, 2009 a regular first class stamp is $0.44 so postage for a square envelope is $0.64Technically, the 6 1/4 x 6 1/4 size classifies the letter as a "Large Envelope" (smallest dimension > 6 1/8 inches), but since it is so close (1/8" !!) they may not enforce the higher Large Envelope rate.See the post office website for more information: http://pe.usps.com/text/dmm100/postage.htm
1n#10 sized envelope 2 if u have a fancy envelope $ if you have a big paper-sized envelope