5.5 x 5.5 Square Envelope Postage
A 5 1/2 in square envelope needs $1.31 at 1 oz and $1.60 at 2 oz. That is letter postage plus the $0.49 nonmachinable surcharge.
Your answer
Nonmachinable letter
+$0.49 surchargeLetter postage plus the nonmachinable surcharge, because it has to be sorted by hand.
- Postage per piece
- $1.31
- 150 invitations
- $196.50
Stamps for each one
1 × Three-Ounce
That pays $0.09 more than needed. For exact postage, ask the post office counter to make up $1.31.
Why
- Square envelopes fail the aspect ratio rule: length divided by height must be between 1.3 and 2.5, and a square is 1. USPS rule
Save money: Switch to an A7.5 rectangle (5.5 x 7.5 in) and save $73.50 on 150 pieces, as long as the weight stays the same.
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150 invitations: $196.50 in postage ($1.31 each, nonmachinable letter)
The classic square invitation
This is the size most "square wedding invitation" listings mean: a 5 1/4 in square card in a 5 1/2 in envelope. It is small enough to be a letter and square enough to be nonmachinable, so it always pays letter postage plus the surcharge.
Shop listings often quote the card size and not the envelope size. Make sure you know which one you are looking at before you compare postage.
What the square costs across a guest list
The surcharge is per piece, so it scales with your list. For 150 invitations, $0.49 each is $73.50 on top of normal postage. A 2 oz square suite comes to $1.60 each.
You cannot avoid it by stamping it as a normal letter and hoping. Short-paid nonmachinable letters are returned to the sender for more postage, which costs you days as well as stamps.
Keeping the square card, losing the surcharge
The surcharge follows the envelope, not the card. A 5 1/4 in square card slides into an A7.5 envelope (5 1/2 x 7 1/2 in), which is a normal rectangle with a ratio of 1.36. The card shifts a little side to side, and a belly band or a rectangular backing card holds it in place.
At the same weight that mailing costs $0.82 instead of $1.31. Whether the matched square envelope is worth the difference is a design call; the square envelope page lays out both sides.
Turning the address does not help
With a rectangle, a failed shape test can sometimes be fixed by writing the address along the other side. A square has no other side. Whichever way you address it, the length and height are equal and the ratio is 1. The only fixes are a different envelope or the surcharge.
Compare the options
| Option | Mail class | Each | For 100 |
|---|---|---|---|
| 5.5 x 5.5 square, 1 oz | Nonmachinable letter | $1.31 | $131.00 |
| A7.5 rectangle, 1 oz | Standard letter | $0.82 | $82.00 |
| 5.5 x 5.5 square, 2 oz | Nonmachinable letter | $1.60 | $160.00 |
| A7.5 rectangle, 2 oz | Standard letter | $1.11 | $111.00 |
Questions and answers
How much postage for a 5.5 x 5.5 square invitation?
$1.31 at 1 oz and $1.60 at 2 oz, including the $0.49 nonmachinable surcharge.
Do square wedding invitations always need extra postage?
Yes. Every square letter fails the aspect ratio rule and pays the $0.49 surcharge, whatever it weighs.
What happens if I use one Forever stamp on a square envelope?
It is short paid. USPS returns short-paid nonmachinable letters to the sender for additional postage.
What rectangle envelope fits a 5.25 inch square card?
An A7.5 envelope, 5 1/2 x 7 1/2 in, holds it and mails without the surcharge.