It depends on where you are mailing it, where to, how you mail it, and the time of year. In the US, a First Class letter takes about 3-5 days. During Christmas (HEAVY mailing season) it may be a bit slower.
How long does it take the post office to deliver bulk mail...specifically from Birmingham to Houston
never
About 2 days
3 days
3 weeks
how long does it take to get a parcel from Nepal to the UK
First class mail is delivered in 3 to 5 days
By first class mail, 1-3 days.
Around 3 days
Atleast two weeks
7 to 10 days
It takes about 4 days