First Class Shipping in an Envelope or Padded Mailer

[djvp53]

Almost everything i ship goes in a crush resistant box but I have a few things listed that could probably go in a padded mailer. Can I use the "First Class Package" rate to send an envelope or a padded mailer first class with tracking?  It seems to be a lot cheaper than the cost to send a letter Priority mail. For instance, I can send an 8 oz box first class to a particular Zip code for $4.80 but the eBay shipping calculator says it would cost $7.09 to send a Priority Mail letter weighing only 2 ounces to the same Zip code.  I know that Priority Mail is theoretically faster but First Class would be fast enough. 

If I entered an envelope's actual dimensions and weight (let's say 12"x9"x0.5" and 2 ounces), it's far cheaper to send it as a First Class package than a Priority Mail envelope.  Any reason I can't do that? 

[whimsyonthewinetrail · Accepted solution]

i do it all the time especially with pattern leaflets and patterns  ..

there are a couple "rules" ... thickness > 1/4"  ... and non-machinable - i add a piece of cardboard to stiffen the package

[djvp53]

Thickness greater than a 1/4" is really good to know.  I might have screwed that up otherwise. That's all there is to it? Is there anything else I need to know?  It might save me a bit on packaging. Envelopes are cheaper than boxes, after all. Thanks!

[nobody*s_perfect]

Yes, First Class package postage is always cheaper than Priority Mail.

You can mail your item as a First Class package as long as it doesn't meet the criteria to be mailed as a letter or flat (AKA Large envelope).  This is important because once in a while a persnickety USPS clerk will spot an ineligible item, and will upgrade it to Priority Mail, resulting in Postage Due.

Anyway, your envelope needs to be:

(1) more than 3/4 inch thick; or

(2) rigid and too large or heavy to mail as a letter (over 3 ounces, or more than 11-1/2 inches long, or more than 6-1/8 inches high, or more than 1/4-inch thick); or

(3) not flat, i.e., a variation in thickness more than 1/4 inch.  

But your 12x9x.5-inch envelope would be considered a flat, rather than a package, if it's not rigid or uneven. Add a couple sheets of cardboard if necessary. First Class package postage is currently priced in 4-ounce increments, so you can add nearly 2 ounces of cardboard to your hypothetical 2-ounce item without incurring extra postage cost. Details here:

https://pe.usps.com/text/dmm300/201.htm#ep1096318

[djvp53]

Thank you! That's very helpful.  I'd hate for my packages to arrive postage due.