The price of a first-class stamp will climb to 44 cents. It's the third year in a row that rates have gone up in May under a new system that allows annual increases as long as they don't exceed the rate of inflation for the year before.
While the increase will bring in added income, the post office continues to struggle financially as more and more lucrative first-class mail is diverted to the Internet, and the recession discourages businesses from sending their usual volume of advertising.
Postmaster General John Potter has asked Congress for permission to reduce mail delivery to five days-a-week. The agency is offering early retirement to workers and making cuts in other areas.
Even so, the rate increase is unlikely to cover the losses and the possibility remains that the post office could run out of money before the end of the budget year, Sept. 30.
The post office could have cited extraordinary circumstances and asked the for larger increases, but officials worried that would only result in a greater decline in mail volume.
Postal officials estimate the increase will cost the average household $3 a year.