In direct mail, aspect ratio is a very important topic, that if ignored, can cause a very large increase in the postage cost of your next direct mail campaign. Consider the case of a 5×7 envelope mailer that is not dense and mailing nationally, and qualifies for Mixed AADC. This piece would require $.288 in postage, or $2,880 for 10,000 pieces. Now, consider the same list, with a 5×6.25 envelope, the postage would be $.647 per piece or $6,470 for a 10,000 piece mailing, costing an additional $3,590 in postage for 10,000 pieces, or an additional $.359 per piece. With these numbers in mind, it is easy to see why aspect ratio is so important.
Aspect Ratio Explained
Aspect ratio in general is a factor on letter sized mail only. The rule states that the width divided by height must be between 1.3 and 2.5 inclusive, meaning that a letter size piece cannot be too square or too long and rectangular. If it does not fall within this category, then it is required to be ran as a non-machinable letter with significant extra postage required. For instance, a 6×9 envelope has an aspect ratio of 1.5, falling with the required range. On the other hand a 5.5×7 mailer has an aspect ratio of 1.27, which does not fall within the acceptable ranges and would cause additional postage to be paid because it is too square. Similarly, a 4×11 size mail piece has an aspect ratio of 2.75, so its aspect ratio is too high, meaning it is too long, so it also fails the aspect ratio test and must be run as a non-machinable letter.
What about flats
Flats and parcels do not have the same requirements as letters when it comes to aspect ratio. A 6.25×6.25 mail piece is categorized as a flat because its height is over the 6.125” maximum for letters, so it can be ran as an automated flat, and using our example above would require $.55 per piece, so more than an automated letter, but less than a non-machinable letter. If on the other hand, it was 6.125×6.125, it would not be eligible as a flat, and would require postage as a non-machinable letter, an almost $1,000 increase on 10,000 pieces of mail.
Keeping Postage Low
Postage is going to be much lower for an automated letter than it is for an automated flat or non-machinable letter. There are certain situations that creating a non-aspect ratio piece will not cause a huge increase in postage, and that is on very dense, walk sequenced mailings. A letter that has walk sequencing applied, and qualifies based on minimum density can run at saturation rates, $.186 per piece. A non-machinable letter that is outside of aspect ratio tolerance can still be ran at saturation rates of $.218 per piece, requiring only $.032 more per postage, or $320 on a mailing of 10,000 pieces.
Keeping aspect ratio in mind when designing mail pieces can prevent an unwanted surprise in additional postage for your next mailing. Ignoring it can become very costly. On the right mailing, however, mailing a non-compliant piece can be done for only a small postage increase, if it is planned for and executed correctly, something that is very important when designing any mail piece.