The cost to finish an attic is $50 to $150 per square foot on average, depending on the purpose of the finished space and the level of finishing or remodeling involved. Converting an attic to a habitable living space costs the most—anywhere from $20,000 to $100,000+ depending on the size and scope of the remodel. Finishing an attic for better storage is the cheapest, starting at around $5,000, since the space is not subject to so many building code requirements.