The prices will change from Monday 6 April
The price of first and second-class stamps is to rise by 3 pence from 6 April, the Royal Mail has announced.
For standard letters weighing up to 100g, a first-class stamp will cost 39p, while second-class will be 30p.
Royal Mail stressed that the increases were within the price limits set by the regulator, Postcomm.
It also said that even after the latest set of rises, delivering stamped mail would remain a loss-making business for Royal Mail.
Last year, Royal Mail lost more than £100m providing the universal mail service.
For large letters, the price of a first-class stamp will go up 9p to 61p while a second-class stamp will rise 5p to 47p.
"Stamped mail remains very affordable and consumers are still receiving excellent value for money," said Luisa Fulci at Royal Mail.
"Most countries in Europe charge more to deliver less."