The average cost of interior painting ranges from $380 to $790 per room excluding the ceilings and trim. Interior painting costs vary between different painters depending on the level of overhead.
In estimating the cost of painting a room, painters start with the amount of paint required to complete the job. They determine the size of the area to cover by adding together the length of the wall and multiplying it by the height from floor to ceiling. They then subtract the area covered by doors and windows to get the area of the printable surface. Painters normally add a little square footage to this amount to account for extra paint that they may need.