Can we ship USPS Priority Mail Cubic in a Priority Mail Tyvek envelope?

If so, do we measure the dimensions of what’s inside or the dimension of the Tyvek envelope?

I sent one at the counter when I noticed it was labeled Priority Mail Cubic and I asked the lady. She asked if I had measured it and I told her yes, but I meant I had measured what’s inside. She weighed it and scanned it and didn’t seem to have any problems with it, so I wonder if it’s really okay? I just hope it doesn’t come back to me or they don’t charge the customer.

It should be the dimensions of the Tyvek envelope with the item inside of it and total weight. The tricky part would be the edges of the Tyvek envelope which create the pointy type end. Because the size of the Tyvek envelope is within the cubic sizing, we would include that extra length created by that pointy type end as it will be more about the weight than the extra 1 inch that you might include for those two ends.


“Ship via Cubic if you use a Priority Mail Tyvek envelope.”

Yes we have done this for quite some time.

We are also doing it for Ground Disadvantage, though we use our own white poly envelopes.

However, we also tape up the envelopes to get the smallest possible package. Sort of what you see on items shipped here from the Asian Basin. Nice and tight, lots of tape.

So far it has worked for us with no additional fees after the fact. We even do it on UPS packages, since size is important for them too.


Ugh, I didn’t do that. I hope they don’t try charging the customer or sending it back to me.

1 Like

You will be fine.
Just make your cubic packages tight in the future.


We forgot the part about taping down those pointed sides as @Image stated. USPS is a little more forgiving on the Tyvek and poly bags when it comes to the sizes as long as it isn’t off by much.

Agree :arrow_up: :arrow_up: :arrow_up: :arrow_up:

1 Like