International mail, postcards, and letters heavier than an ounce may cost more to send if a new postal service proposal is approved.

“Forever Stamps” would remain 49 cents each. Letters weighing more than one ounce would increase from 21 to 22 cents per additional ounce, letters to all international destinations would rise from $1.15 to $1.20, and postcard prices would go up from 34 to 35 cents per card.

If approved, the new rates would go into effect April 26.