dimensions for usps priority mail flat rate boxes?

[occasionally-vintage]

total newbie question (with probably an obvious answer) - but when measuring the dimensions for a flat-rate priority mail package, do you just enter the dimensions of the box? or is it a measurement of the content inside?

i feel pretty foolish even asking this question because the answer seems obvious (it's the dimensions of the flat-rate box itself), but i'm still pretty new to this and i just wanted to be totally certain.

thanks!

[nobody*s_perfect · Accepted solution]

Box dimensions are always entered as the exterior actual dimensions, to the nearest full inch.

For the flat rate boxes, accuracy isn't important.  The only time that package measurements will affect the postage price is if the volume of the box is more than 1 cubic foot (1728 cubic inches). None  of the flat rate boxes comes near that.

[evelyb30]

It's the box.  They don't care about what's inside unless it's fragile. (and many would say not even then)  As long as the box isn't over the maximum stated weight the contents aren't relevant.  If it's fragile and so marked, they MAY throw it around a little less and not park an anvil on the box.  May.

[occasionally-vintage]

excellent, i'm glad i asked - i really appreciate the detailed answers!!

[pooh333piglet]

Hahaha!!!   MAY 

So true!!!

[evelyb30]

I learned the hard way not to trust the USPS around fragile stuff.  Pack like it's going to be drop-kicked at least once. 

 The USPS prefers flat sided packaging, but I put really small bits in plastic Easter eggs.  The item and tissue go into the eggs, which are then packing taped shut.  The egg goes into a bubble mailer.  They aren't flat, so heftier packages can't land on them squarely.  It's worked well for years.  As a bonus, the eggs are cheap and people love them.