The price for a one-ounce first-class stamp will increase from 41 to 42 cents May 12, the U.S. Postal Service announced Friday.

Prices for other mailing services, such as standard mail, periodicals, package services (including single-piece parcel post) and special services will also change. The average increase by class of mail is at or below the rate of inflation as measured by the Consumer Price Index, according to the Postal Service.

Prices for all postal products and services are available online.

The Postal Service is also offering the Forever Stamp for 41 cents, said Postmaster General John Potter. "We encourage Americans to buy Forever Stamps now for 41 cents, because, like the name suggests, they are good forever," he said. The price goes up to 42 cents May 12.