U.S. Postal Service Resources

Calculate Domestic Postage (USPS)
Easily calculate retail postage rates and estimated delivery times.

Calculate International Postage (USPS)
Easily calculate global postage rates and estimated delivery times.

Calculate Business Postage (USPS)
Calculate domestic postage for all volume discount mail.

Business Mail 101 (USPS)
Excellent overview of business mailing basics for the small (and large) businessperson.