Question: how much does it cost to add an extra bedroom?
Answer: The cost to add a bedroom is $100 to $155 per square foot, or about $10,300 to $24,900 on average. A small 12x12 bedroom (144-square-feet) with a foundation and a roof will cost in the neighborhood of $12,400 to $22,300 if you choose to add it to the side of the house.