Despite using calculate shipping, it under charged shipping fees

[camper_65]

Hello all,

When I list my books, I always measure the package the book will fit in, get the accurate weight with the package, cardboard protection, and book so that I know I'm using the right weight on my listing.  Despite this, I just had a book sell and the shipping was about $1.00 short for the first class shipping choice the buyer picked.  I have my listing set to both media mail and first class as optional shipping choices (and a few with media mail and priority mail when it's a heavier book).  Is there something wrong with the shipping calculator when giving more than one option of USPS shipping types?  This isn't the first time it happened, but this time it wasn't even the amount that media mail cost, it was lower than that and I double-checked the weight, it was correct.  Note that I don't post listings using my phone only my computer and not using a "relist" entry.

[nobody*s_perfect · Accepted solution]

In the shipping calculator menu for "Package type" you must have checked off "Large envelope" rather than "Package/thick envelope."

[camper_65]

I just went through the remaining book listings and fixed that, apparently I did have some marked as large envelope instead of package.  They are all corrected now. Thanks.

[meemaw.1]

To all of those explaining about selecting "large envelop" - What I don't understand is WHY is there even an option for "large envelop"  ?  My package IS in a large envelope and it still undercharged for First Class Shipping. It already undercharged buyer for shipping and when I actually try to ship there is NO choice for "large envelop" JUST 1st class which will cost me more than the buyer paid. So again, why is this option even there????

[nobody*s_perfect]

The option is there so sellers can choose it.  eBay lets sellers set up listings with all of the USPS options, even those that eBay doesn't sell such as First class letters and flats, and Retail Ground.   eBay only sells labels for packages, not for First Class letters or flats (AKA Large envelopes) so you'd have to purchase that postage at the  Post Office or just put stamps on your envelope.  

USPS has 3 types of First Class postage: Letters, flats (AKA Large envelope) and packages.  An envelope could fall into any of those 3 categories depending on factors like weight, dimensions (including thickness), rigidity etc.  The USPS's definition of a flat (AKA Large envelope) includes a thickness limit of 3/4 inch, and the envelope must not be rigid.