Postage rates go up annually in May, with the new prices announced in February. The overall change is tied to the rate of inflation in the year before.
While the new 44-cent rate covers the first ounce of first-class mail, the price for each additional ounce will remain unchanged at 17-cents.
Postal officials estimate the increase will cost the average household $3-a-year.
Buffeted by rising costs and declining mail volume, the Postal Service lost $2.8 billion last year and, unless the economy turns around, is headed toward much larger losses this year.
The agency could have cited extraordinary circumstances and asked the independent Postal Regulatory Commission for larger increases, but officials felt that would only result in a greater decline in mail volume.
The post office has been cutting costs, reducing work hours, and has asked Congress to ease requirements for advance funds for retiree benefits and to allow mail to be delivered five days a week instead of six.
Other changes taking effect May 11:
o The postcard stamp increases 1-cent to 27 cents.
o The first ounce of a large envelope increases 5 cents to 88 cents.
o The first ounce of a parcel increases 5 cents to $1.22.
o New international postcard and letter prices are, for one ounce, 75 cents to Canada; 79 cents to Mexico; and 98 cents elsewhere.
Most Postal Service shipping services prices were adjusted in January and will not change in May.
On the Net:
U.S. Postal Service: http://www.usps.com