State Estimated Travel Days

i have an excel sheet that is huge and covers all customers weve shipped to all over the us. i need to add expected delivery dates to each and every one, basically a code that if you set me on the right path i can finish the basic idea is
shipdate| City,State | Expected delivery date|
5/12/14 | Seattle, WA| 5/13/14

Where in this single case it takes one day for the product to reach washington from our location. and i need to be able to make it large enough to encompass all 48 states(we dont ship to hawaii or alaska)

a push in the right direction would be amazing!

Not much to work with here. Are you wanting to calculate an expected delivery date based upon known shipping times (if so where is that data), or are you wanting to calculate the shipping days based upon the ship date and the expected delivery date (if so use =NETWORKDAYS).

That is about as clear as mud. I hope you are able to find a solution to your problem. Best wishes.